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postgresql/src/backend/parser/parse_expr.c

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/*-------------------------------------------------------------------------
*
* parse_expr.c
* handle expressions in parser
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/parser/parse_expr.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/analyze.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_collate.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/timestamp.h"
#include "utils/xml.h"
/* GUC parameters */
bool Transform_null_equals = false;
static Node *transformExprRecurse(ParseState *pstate, Node *expr);
static Node *transformParamRef(ParseState *pstate, ParamRef *pref);
static Node *transformAExprOp(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAny(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAll(ParseState *pstate, A_Expr *a);
static Node *transformAExprDistinct(ParseState *pstate, A_Expr *a);
static Node *transformAExprNullIf(ParseState *pstate, A_Expr *a);
static Node *transformAExprIn(ParseState *pstate, A_Expr *a);
static Node *transformAExprBetween(ParseState *pstate, A_Expr *a);
static Node *transformBoolExpr(ParseState *pstate, BoolExpr *a);
static Node *transformFuncCall(ParseState *pstate, FuncCall *fn);
static Node *transformMultiAssignRef(ParseState *pstate, MultiAssignRef *maref);
static Node *transformCaseExpr(ParseState *pstate, CaseExpr *c);
static Node *transformSubLink(ParseState *pstate, SubLink *sublink);
static Node *transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
Oid array_type, Oid element_type, int32 typmod);
static Node *transformRowExpr(ParseState *pstate, RowExpr *r, bool allowDefault);
static Node *transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c);
static Node *transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m);
static Node *transformSQLValueFunction(ParseState *pstate,
SQLValueFunction *svf);
static Node *transformXmlExpr(ParseState *pstate, XmlExpr *x);
static Node *transformXmlSerialize(ParseState *pstate, XmlSerialize *xs);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr);
static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
static Node *transformWholeRowRef(ParseState *pstate,
ParseNamespaceItem *nsitem,
int sublevels_up, int location);
static Node *transformIndirection(ParseState *pstate, A_Indirection *ind);
static Node *transformTypeCast(ParseState *pstate, TypeCast *tc);
static Node *transformCollateClause(ParseState *pstate, CollateClause *c);
static Node *transformJsonObjectConstructor(ParseState *pstate,
JsonObjectConstructor *ctor);
static Node *transformJsonArrayConstructor(ParseState *pstate,
JsonArrayConstructor *ctor);
static Node *transformJsonArrayQueryConstructor(ParseState *pstate,
JsonArrayQueryConstructor *ctor);
static Node *transformJsonObjectAgg(ParseState *pstate, JsonObjectAgg *agg);
static Node *transformJsonArrayAgg(ParseState *pstate, JsonArrayAgg *agg);
static Node *transformJsonIsPredicate(ParseState *pstate, JsonIsPredicate *pred);
static Node *make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location);
static Node *make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow, int location);
static Expr *make_distinct_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree, int location);
static Node *make_nulltest_from_distinct(ParseState *pstate,
A_Expr *distincta, Node *arg);
/*
* transformExpr -
* Analyze and transform expressions. Type checking and type casting is
* done here. This processing converts the raw grammar output into
* expression trees with fully determined semantics.
*/
Node *
transformExpr(ParseState *pstate, Node *expr, ParseExprKind exprKind)
{
Node *result;
ParseExprKind sv_expr_kind;
/* Save and restore identity of expression type we're parsing */
Assert(exprKind != EXPR_KIND_NONE);
sv_expr_kind = pstate->p_expr_kind;
pstate->p_expr_kind = exprKind;
result = transformExprRecurse(pstate, expr);
pstate->p_expr_kind = sv_expr_kind;
return result;
}
static Node *
transformExprRecurse(ParseState *pstate, Node *expr)
{
Node *result;
if (expr == NULL)
return NULL;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
switch (nodeTag(expr))
{
case T_ColumnRef:
result = transformColumnRef(pstate, (ColumnRef *) expr);
break;
case T_ParamRef:
result = transformParamRef(pstate, (ParamRef *) expr);
break;
case T_A_Const:
result = (Node *) make_const(pstate, (A_Const *) expr);
break;
case T_A_Indirection:
result = transformIndirection(pstate, (A_Indirection *) expr);
break;
case T_A_ArrayExpr:
result = transformArrayExpr(pstate, (A_ArrayExpr *) expr,
InvalidOid, InvalidOid, -1);
break;
case T_TypeCast:
result = transformTypeCast(pstate, (TypeCast *) expr);
break;
case T_CollateClause:
result = transformCollateClause(pstate, (CollateClause *) expr);
break;
case T_A_Expr:
{
A_Expr *a = (A_Expr *) expr;
switch (a->kind)
{
case AEXPR_OP:
result = transformAExprOp(pstate, a);
break;
case AEXPR_OP_ANY:
result = transformAExprOpAny(pstate, a);
break;
case AEXPR_OP_ALL:
result = transformAExprOpAll(pstate, a);
break;
case AEXPR_DISTINCT:
case AEXPR_NOT_DISTINCT:
result = transformAExprDistinct(pstate, a);
break;
case AEXPR_NULLIF:
result = transformAExprNullIf(pstate, a);
break;
case AEXPR_IN:
result = transformAExprIn(pstate, a);
break;
case AEXPR_LIKE:
case AEXPR_ILIKE:
case AEXPR_SIMILAR:
/* we can transform these just like AEXPR_OP */
result = transformAExprOp(pstate, a);
break;
case AEXPR_BETWEEN:
case AEXPR_NOT_BETWEEN:
case AEXPR_BETWEEN_SYM:
case AEXPR_NOT_BETWEEN_SYM:
result = transformAExprBetween(pstate, a);
break;
default:
elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
result = NULL; /* keep compiler quiet */
break;
}
break;
}
case T_BoolExpr:
result = transformBoolExpr(pstate, (BoolExpr *) expr);
break;
case T_FuncCall:
result = transformFuncCall(pstate, (FuncCall *) expr);
break;
case T_MultiAssignRef:
result = transformMultiAssignRef(pstate, (MultiAssignRef *) expr);
break;
case T_GroupingFunc:
result = transformGroupingFunc(pstate, (GroupingFunc *) expr);
break;
case T_NamedArgExpr:
{
NamedArgExpr *na = (NamedArgExpr *) expr;
na->arg = (Expr *) transformExprRecurse(pstate, (Node *) na->arg);
result = expr;
break;
}
case T_SubLink:
result = transformSubLink(pstate, (SubLink *) expr);
break;
case T_CaseExpr:
result = transformCaseExpr(pstate, (CaseExpr *) expr);
break;
case T_RowExpr:
result = transformRowExpr(pstate, (RowExpr *) expr, false);
break;
case T_CoalesceExpr:
result = transformCoalesceExpr(pstate, (CoalesceExpr *) expr);
break;
case T_MinMaxExpr:
result = transformMinMaxExpr(pstate, (MinMaxExpr *) expr);
break;
case T_SQLValueFunction:
result = transformSQLValueFunction(pstate,
(SQLValueFunction *) expr);
break;
case T_XmlExpr:
result = transformXmlExpr(pstate, (XmlExpr *) expr);
break;
case T_XmlSerialize:
result = transformXmlSerialize(pstate, (XmlSerialize *) expr);
break;
case T_NullTest:
{
NullTest *n = (NullTest *) expr;
n->arg = (Expr *) transformExprRecurse(pstate, (Node *) n->arg);
/* the argument can be any type, so don't coerce it */
n->argisrow = type_is_rowtype(exprType((Node *) n->arg));
result = expr;
break;
}
case T_BooleanTest:
result = transformBooleanTest(pstate, (BooleanTest *) expr);
break;
case T_CurrentOfExpr:
result = transformCurrentOfExpr(pstate, (CurrentOfExpr *) expr);
break;
/*
* In all places where DEFAULT is legal, the caller should have
* processed it rather than passing it to transformExpr().
*/
case T_SetToDefault:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("DEFAULT is not allowed in this context"),
parser_errposition(pstate,
((SetToDefault *) expr)->location)));
break;
/*
* CaseTestExpr doesn't require any processing; it is only
* injected into parse trees in a fully-formed state.
*
* Ordinarily we should not see a Var here, but it is convenient
* for transformJoinUsingClause() to create untransformed operator
* trees containing already-transformed Vars. The best
* alternative would be to deconstruct and reconstruct column
* references, which seems expensively pointless. So allow it.
*/
case T_CaseTestExpr:
case T_Var:
{
result = (Node *) expr;
break;
}
case T_JsonObjectConstructor:
result = transformJsonObjectConstructor(pstate, (JsonObjectConstructor *) expr);
break;
case T_JsonArrayConstructor:
result = transformJsonArrayConstructor(pstate, (JsonArrayConstructor *) expr);
break;
case T_JsonArrayQueryConstructor:
result = transformJsonArrayQueryConstructor(pstate, (JsonArrayQueryConstructor *) expr);
break;
case T_JsonObjectAgg:
result = transformJsonObjectAgg(pstate, (JsonObjectAgg *) expr);
break;
case T_JsonArrayAgg:
result = transformJsonArrayAgg(pstate, (JsonArrayAgg *) expr);
break;
case T_JsonIsPredicate:
result = transformJsonIsPredicate(pstate, (JsonIsPredicate *) expr);
break;
default:
/* should not reach here */
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
result = NULL; /* keep compiler quiet */
break;
}
return result;
}
/*
* helper routine for delivering "column does not exist" error message
*
* (Usually we don't have to work this hard, but the general case of field
* selection from an arbitrary node needs it.)
*/
static void
unknown_attribute(ParseState *pstate, Node *relref, const char *attname,
int location)
{
RangeTblEntry *rte;
if (IsA(relref, Var) &&
((Var *) relref)->varattno == InvalidAttrNumber)
{
/* Reference the RTE by alias not by actual table name */
rte = GetRTEByRangeTablePosn(pstate,
((Var *) relref)->varno,
((Var *) relref)->varlevelsup);
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %s.%s does not exist",
rte->eref->aliasname, attname),
parser_errposition(pstate, location)));
}
else
{
/* Have to do it by reference to the type of the expression */
Oid relTypeId = exprType(relref);
if (ISCOMPLEX(relTypeId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" not found in data type %s",
attname, format_type_be(relTypeId)),
parser_errposition(pstate, location)));
else if (relTypeId == RECORDOID)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("could not identify column \"%s\" in record data type",
attname),
parser_errposition(pstate, location)));
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("column notation .%s applied to type %s, "
"which is not a composite type",
attname, format_type_be(relTypeId)),
parser_errposition(pstate, location)));
}
}
static Node *
transformIndirection(ParseState *pstate, A_Indirection *ind)
{
Node *last_srf = pstate->p_last_srf;
Node *result = transformExprRecurse(pstate, ind->arg);
List *subscripts = NIL;
int location = exprLocation(result);
ListCell *i;
/*
* We have to split any field-selection operations apart from
* subscripting. Adjacent A_Indices nodes have to be treated as a single
* multidimensional subscript operation.
*/
foreach(i, ind->indirection)
{
Node *n = lfirst(i);
if (IsA(n, A_Indices))
subscripts = lappend(subscripts, n);
else if (IsA(n, A_Star))
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("row expansion via \"*\" is not supported here"),
parser_errposition(pstate, location)));
}
else
{
Node *newresult;
Assert(IsA(n, String));
/* process subscripts before this field selection */
if (subscripts)
result = (Node *) transformContainerSubscripts(pstate,
result,
exprType(result),
exprTypmod(result),
subscripts,
false);
subscripts = NIL;
newresult = ParseFuncOrColumn(pstate,
list_make1(n),
list_make1(result),
last_srf,
NULL,
false,
location);
if (newresult == NULL)
unknown_attribute(pstate, result, strVal(n), location);
result = newresult;
}
}
/* process trailing subscripts, if any */
if (subscripts)
result = (Node *) transformContainerSubscripts(pstate,
result,
exprType(result),
exprTypmod(result),
subscripts,
false);
return result;
}
/*
* Transform a ColumnRef.
*
* If you find yourself changing this code, see also ExpandColumnRefStar.
*/
static Node *
transformColumnRef(ParseState *pstate, ColumnRef *cref)
{
Node *node = NULL;
char *nspname = NULL;
char *relname = NULL;
char *colname = NULL;
ParseNamespaceItem *nsitem;
int levels_up;
enum
{
CRERR_NO_COLUMN,
CRERR_NO_RTE,
CRERR_WRONG_DB,
CRERR_TOO_MANY
} crerr = CRERR_NO_COLUMN;
const char *err;
/*
* Check to see if the column reference is in an invalid place within the
* query. We allow column references in most places, except in default
* expressions and partition bound expressions.
*/
err = NULL;
switch (pstate->p_expr_kind)
{
case EXPR_KIND_NONE:
Assert(false); /* can't happen */
break;
case EXPR_KIND_OTHER:
case EXPR_KIND_JOIN_ON:
case EXPR_KIND_JOIN_USING:
case EXPR_KIND_FROM_SUBSELECT:
case EXPR_KIND_FROM_FUNCTION:
case EXPR_KIND_WHERE:
case EXPR_KIND_POLICY:
case EXPR_KIND_HAVING:
case EXPR_KIND_FILTER:
case EXPR_KIND_WINDOW_PARTITION:
case EXPR_KIND_WINDOW_ORDER:
case EXPR_KIND_WINDOW_FRAME_RANGE:
case EXPR_KIND_WINDOW_FRAME_ROWS:
case EXPR_KIND_WINDOW_FRAME_GROUPS:
case EXPR_KIND_SELECT_TARGET:
case EXPR_KIND_INSERT_TARGET:
case EXPR_KIND_UPDATE_SOURCE:
case EXPR_KIND_UPDATE_TARGET:
case EXPR_KIND_MERGE_WHEN:
case EXPR_KIND_GROUP_BY:
case EXPR_KIND_ORDER_BY:
case EXPR_KIND_DISTINCT_ON:
case EXPR_KIND_LIMIT:
case EXPR_KIND_OFFSET:
case EXPR_KIND_RETURNING:
case EXPR_KIND_VALUES:
case EXPR_KIND_VALUES_SINGLE:
case EXPR_KIND_CHECK_CONSTRAINT:
case EXPR_KIND_DOMAIN_CHECK:
case EXPR_KIND_FUNCTION_DEFAULT:
case EXPR_KIND_INDEX_EXPRESSION:
case EXPR_KIND_INDEX_PREDICATE:
case EXPR_KIND_STATS_EXPRESSION:
case EXPR_KIND_ALTER_COL_TRANSFORM:
case EXPR_KIND_EXECUTE_PARAMETER:
case EXPR_KIND_TRIGGER_WHEN:
case EXPR_KIND_PARTITION_EXPRESSION:
case EXPR_KIND_CALL_ARGUMENT:
case EXPR_KIND_COPY_WHERE:
case EXPR_KIND_GENERATED_COLUMN:
case EXPR_KIND_CYCLE_MARK:
/* okay */
break;
case EXPR_KIND_COLUMN_DEFAULT:
err = _("cannot use column reference in DEFAULT expression");
break;
case EXPR_KIND_PARTITION_BOUND:
err = _("cannot use column reference in partition bound expression");
break;
/*
* There is intentionally no default: case here, so that the
* compiler will warn if we add a new ParseExprKind without
* extending this switch. If we do see an unrecognized value at
* runtime, the behavior will be the same as for EXPR_KIND_OTHER,
* which is sane anyway.
*/
}
if (err)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg_internal("%s", err),
parser_errposition(pstate, cref->location)));
/*
* Give the PreParseColumnRefHook, if any, first shot. If it returns
* non-null then that's all, folks.
*/
if (pstate->p_pre_columnref_hook != NULL)
{
node = pstate->p_pre_columnref_hook(pstate, cref);
if (node != NULL)
return node;
}
/*----------
* The allowed syntaxes are:
*
* A First try to resolve as unqualified column name;
* if no luck, try to resolve as unqualified table name (A.*).
* A.B A is an unqualified table name; B is either a
* column or function name (trying column name first).
* A.B.C schema A, table B, col or func name C.
* A.B.C.D catalog A, schema B, table C, col or func D.
* A.* A is an unqualified table name; means whole-row value.
* A.B.* whole-row value of table B in schema A.
* A.B.C.* whole-row value of table C in schema B in catalog A.
*
* We do not need to cope with bare "*"; that will only be accepted by
* the grammar at the top level of a SELECT list, and transformTargetList
* will take care of it before it ever gets here. Also, "A.*" etc will
* be expanded by transformTargetList if they appear at SELECT top level,
* so here we are only going to see them as function or operator inputs.
*
* Currently, if a catalog name is given then it must equal the current
* database name; we check it here and then discard it.
*----------
*/
switch (list_length(cref->fields))
{
case 1:
{
Node *field1 = (Node *) linitial(cref->fields);
colname = strVal(field1);
/* Try to identify as an unqualified column */
node = colNameToVar(pstate, colname, false, cref->location);
if (node == NULL)
{
/*
* Not known as a column of any range-table entry.
*
* Try to find the name as a relation. Note that only
* relations already entered into the rangetable will be
* recognized.
*
* This is a hack for backwards compatibility with
* PostQUEL-inspired syntax. The preferred form now is
* "rel.*".
*/
nsitem = refnameNamespaceItem(pstate, NULL, colname,
cref->location,
&levels_up);
if (nsitem)
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
}
break;
}
case 2:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
relname = strVal(field1);
/* Locate the referenced nsitem */
nsitem = refnameNamespaceItem(pstate, nspname, relname,
cref->location,
&levels_up);
if (nsitem == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field2, A_Star))
{
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
break;
}
colname = strVal(field2);
/* Try to identify as a column of the nsitem */
node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
pstate->p_last_srf,
NULL,
false,
cref->location);
}
break;
}
case 3:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
Node *field3 = (Node *) lthird(cref->fields);
nspname = strVal(field1);
relname = strVal(field2);
/* Locate the referenced nsitem */
nsitem = refnameNamespaceItem(pstate, nspname, relname,
cref->location,
&levels_up);
if (nsitem == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field3, A_Star))
{
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
break;
}
colname = strVal(field3);
/* Try to identify as a column of the nsitem */
node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
pstate->p_last_srf,
NULL,
false,
cref->location);
}
break;
}
case 4:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
Node *field3 = (Node *) lthird(cref->fields);
Node *field4 = (Node *) lfourth(cref->fields);
char *catname;
catname = strVal(field1);
nspname = strVal(field2);
relname = strVal(field3);
/*
* We check the catalog name and then ignore it.
*/
if (strcmp(catname, get_database_name(MyDatabaseId)) != 0)
{
crerr = CRERR_WRONG_DB;
break;
}
/* Locate the referenced nsitem */
nsitem = refnameNamespaceItem(pstate, nspname, relname,
cref->location,
&levels_up);
if (nsitem == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field4, A_Star))
{
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
break;
}
colname = strVal(field4);
/* Try to identify as a column of the nsitem */
node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, nsitem, levels_up,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
pstate->p_last_srf,
NULL,
false,
cref->location);
}
break;
}
default:
crerr = CRERR_TOO_MANY; /* too many dotted names */
break;
}
/*
* Now give the PostParseColumnRefHook, if any, a chance. We pass the
* translation-so-far so that it can throw an error if it wishes in the
* case that it has a conflicting interpretation of the ColumnRef. (If it
* just translates anyway, we'll throw an error, because we can't undo
* whatever effects the preceding steps may have had on the pstate.) If it
* returns NULL, use the standard translation, or throw a suitable error
* if there is none.
*/
if (pstate->p_post_columnref_hook != NULL)
{
Node *hookresult;
hookresult = pstate->p_post_columnref_hook(pstate, cref, node);
if (node == NULL)
node = hookresult;
else if (hookresult != NULL)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("column reference \"%s\" is ambiguous",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
}
/*
* Throw error if no translation found.
*/
if (node == NULL)
{
switch (crerr)
{
case CRERR_NO_COLUMN:
errorMissingColumn(pstate, relname, colname, cref->location);
break;
case CRERR_NO_RTE:
errorMissingRTE(pstate, makeRangeVar(nspname, relname,
cref->location));
break;
case CRERR_WRONG_DB:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cross-database references are not implemented: %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
break;
case CRERR_TOO_MANY:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("improper qualified name (too many dotted names): %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
break;
}
}
return node;
}
static Node *
transformParamRef(ParseState *pstate, ParamRef *pref)
{
Node *result;
/*
* The core parser knows nothing about Params. If a hook is supplied,
* call it. If not, or if the hook returns NULL, throw a generic error.
*/
if (pstate->p_paramref_hook != NULL)
result = pstate->p_paramref_hook(pstate, pref);
else
result = NULL;
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d", pref->number),
parser_errposition(pstate, pref->location)));
return result;
}
/* Test whether an a_expr is a plain NULL constant or not */
static bool
exprIsNullConstant(Node *arg)
{
if (arg && IsA(arg, A_Const))
{
A_Const *con = (A_Const *) arg;
if (con->isnull)
return true;
}
return false;
}
static Node *
transformAExprOp(ParseState *pstate, A_Expr *a)
{
Node *lexpr = a->lexpr;
Node *rexpr = a->rexpr;
Node *result;
/*
* Special-case "foo = NULL" and "NULL = foo" for compatibility with
* standards-broken products (like Microsoft's). Turn these into IS NULL
* exprs. (If either side is a CaseTestExpr, then the expression was
* generated internally from a CASE-WHEN expression, and
* transform_null_equals does not apply.)
*/
if (Transform_null_equals &&
list_length(a->name) == 1 &&
strcmp(strVal(linitial(a->name)), "=") == 0 &&
(exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)) &&
(!IsA(lexpr, CaseTestExpr) && !IsA(rexpr, CaseTestExpr)))
{
NullTest *n = makeNode(NullTest);
n->nulltesttype = IS_NULL;
n->location = a->location;
if (exprIsNullConstant(lexpr))
n->arg = (Expr *) rexpr;
else
n->arg = (Expr *) lexpr;
result = transformExprRecurse(pstate, (Node *) n);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, SubLink) &&
((SubLink *) rexpr)->subLinkType == EXPR_SUBLINK)
{
/*
* Convert "row op subselect" into a ROWCOMPARE sublink. Formerly the
* grammar did this, but now that a row construct is allowed anywhere
* in expressions, it's easier to do it here.
*/
SubLink *s = (SubLink *) rexpr;
s->subLinkType = ROWCOMPARE_SUBLINK;
s->testexpr = lexpr;
s->operName = a->name;
s->location = a->location;
result = transformExprRecurse(pstate, (Node *) s);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* ROW() op ROW() is handled specially */
lexpr = transformExprRecurse(pstate, lexpr);
rexpr = transformExprRecurse(pstate, rexpr);
result = make_row_comparison_op(pstate,
a->name,
castNode(RowExpr, lexpr)->args,
castNode(RowExpr, rexpr)->args,
a->location);
}
else
{
/* Ordinary scalar operator */
Node *last_srf = pstate->p_last_srf;
lexpr = transformExprRecurse(pstate, lexpr);
rexpr = transformExprRecurse(pstate, rexpr);
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr,
last_srf,
a->location);
}
return result;
}
static Node *
transformAExprOpAny(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExprRecurse(pstate, a->lexpr);
Node *rexpr = transformExprRecurse(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
true,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprOpAll(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExprRecurse(pstate, a->lexpr);
Node *rexpr = transformExprRecurse(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
false,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprDistinct(ParseState *pstate, A_Expr *a)
{
Node *lexpr = a->lexpr;
Node *rexpr = a->rexpr;
Node *result;
/*
* If either input is an undecorated NULL literal, transform to a NullTest
* on the other input. That's simpler to process than a full DistinctExpr,
* and it avoids needing to require that the datatype have an = operator.
*/
if (exprIsNullConstant(rexpr))
return make_nulltest_from_distinct(pstate, a, lexpr);
if (exprIsNullConstant(lexpr))
return make_nulltest_from_distinct(pstate, a, rexpr);
lexpr = transformExprRecurse(pstate, lexpr);
rexpr = transformExprRecurse(pstate, rexpr);
if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* ROW() op ROW() is handled specially */
result = make_row_distinct_op(pstate, a->name,
(RowExpr *) lexpr,
(RowExpr *) rexpr,
a->location);
}
else
{
/* Ordinary scalar operator */
result = (Node *) make_distinct_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
}
/*
* If it's NOT DISTINCT, we first build a DistinctExpr and then stick a
* NOT on top.
*/
if (a->kind == AEXPR_NOT_DISTINCT)
result = (Node *) makeBoolExpr(NOT_EXPR,
list_make1(result),
a->location);
return result;
}
static Node *
transformAExprNullIf(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExprRecurse(pstate, a->lexpr);
Node *rexpr = transformExprRecurse(pstate, a->rexpr);
OpExpr *result;
result = (OpExpr *) make_op(pstate,
a->name,
lexpr,
rexpr,
pstate->p_last_srf,
a->location);
/*
* The comparison operator itself should yield boolean ...
*/
if (result->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("NULLIF requires = operator to yield boolean"),
parser_errposition(pstate, a->location)));
if (result->opretset)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
/* translator: %s is name of a SQL construct, eg NULLIF */
errmsg("%s must not return a set", "NULLIF"),
parser_errposition(pstate, a->location)));
/*
* ... but the NullIfExpr will yield the first operand's type.
*/
result->opresulttype = exprType((Node *) linitial(result->args));
/*
* We rely on NullIfExpr and OpExpr being the same struct
*/
NodeSetTag(result, T_NullIfExpr);
return (Node *) result;
}
static Node *
transformAExprIn(ParseState *pstate, A_Expr *a)
{
Node *result = NULL;
Node *lexpr;
List *rexprs;
List *rvars;
List *rnonvars;
bool useOr;
ListCell *l;
/*
* If the operator is <>, combine with AND not OR.
*/
if (strcmp(strVal(linitial(a->name)), "<>") == 0)
useOr = false;
else
useOr = true;
/*
* We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
* possible if there is a suitable array type available. If not, we fall
* back to a boolean condition tree with multiple copies of the lefthand
* expression. Also, any IN-list items that contain Vars are handled as
* separate boolean conditions, because that gives the planner more scope
* for optimization on such clauses.
*
* First step: transform all the inputs, and detect whether any contain
* Vars.
*/
lexpr = transformExprRecurse(pstate, a->lexpr);
rexprs = rvars = rnonvars = NIL;
foreach(l, (List *) a->rexpr)
{
Node *rexpr = transformExprRecurse(pstate, lfirst(l));
rexprs = lappend(rexprs, rexpr);
if (contain_vars_of_level(rexpr, 0))
rvars = lappend(rvars, rexpr);
else
rnonvars = lappend(rnonvars, rexpr);
}
/*
* ScalarArrayOpExpr is only going to be useful if there's more than one
* non-Var righthand item.
*/
if (list_length(rnonvars) > 1)
{
List *allexprs;
Oid scalar_type;
Oid array_type;
/*
* Try to select a common type for the array elements. Note that
* since the LHS' type is first in the list, it will be preferred when
* there is doubt (eg, when all the RHS items are unknown literals).
*
* Note: use list_concat here not lcons, to avoid damaging rnonvars.
*/
allexprs = list_concat(list_make1(lexpr), rnonvars);
scalar_type = select_common_type(pstate, allexprs, NULL, NULL);
/* We have to verify that the selected type actually works */
if (OidIsValid(scalar_type) &&
!verify_common_type(scalar_type, allexprs))
scalar_type = InvalidOid;
/*
* Do we have an array type to use? Aside from the case where there
* isn't one, we don't risk using ScalarArrayOpExpr when the common
* type is RECORD, because the RowExpr comparison logic below can cope
* with some cases of non-identical row types.
*/
if (OidIsValid(scalar_type) && scalar_type != RECORDOID)
array_type = get_array_type(scalar_type);
else
array_type = InvalidOid;
if (array_type != InvalidOid)
{
/*
* OK: coerce all the right-hand non-Var inputs to the common type
* and build an ArrayExpr for them.
*/
List *aexprs;
ArrayExpr *newa;
aexprs = NIL;
foreach(l, rnonvars)
{
Node *rexpr = (Node *) lfirst(l);
rexpr = coerce_to_common_type(pstate, rexpr,
scalar_type,
"IN");
aexprs = lappend(aexprs, rexpr);
}
newa = makeNode(ArrayExpr);
newa->array_typeid = array_type;
/* array_collid will be set by parse_collate.c */
newa->element_typeid = scalar_type;
newa->elements = aexprs;
newa->multidims = false;
newa->location = -1;
result = (Node *) make_scalar_array_op(pstate,
a->name,
useOr,
lexpr,
(Node *) newa,
a->location);
/* Consider only the Vars (if any) in the loop below */
rexprs = rvars;
}
}
/*
* Must do it the hard way, ie, with a boolean expression tree.
*/
foreach(l, rexprs)
{
Node *rexpr = (Node *) lfirst(l);
Node *cmp;
if (IsA(lexpr, RowExpr) &&
IsA(rexpr, RowExpr))
{
/* ROW() op ROW() is handled specially */
cmp = make_row_comparison_op(pstate,
a->name,
copyObject(((RowExpr *) lexpr)->args),
((RowExpr *) rexpr)->args,
a->location);
}
else
{
/* Ordinary scalar operator */
cmp = (Node *) make_op(pstate,
a->name,
copyObject(lexpr),
rexpr,
pstate->p_last_srf,
a->location);
}
cmp = coerce_to_boolean(pstate, cmp, "IN");
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(useOr ? OR_EXPR : AND_EXPR,
list_make2(result, cmp),
a->location);
}
return result;
}
static Node *
transformAExprBetween(ParseState *pstate, A_Expr *a)
{
Node *aexpr;
Node *bexpr;
Node *cexpr;
Node *result;
Node *sub1;
Node *sub2;
List *args;
/* Deconstruct A_Expr into three subexprs */
aexpr = a->lexpr;
args = castNode(List, a->rexpr);
Assert(list_length(args) == 2);
bexpr = (Node *) linitial(args);
cexpr = (Node *) lsecond(args);
/*
* Build the equivalent comparison expression. Make copies of
* multiply-referenced subexpressions for safety. (XXX this is really
* wrong since it results in multiple runtime evaluations of what may be
* volatile expressions ...)
*
* Ideally we would not use hard-wired operators here but instead use
* opclasses. However, mixed data types and other issues make this
* difficult:
* http://archives.postgresql.org/pgsql-hackers/2008-08/msg01142.php
*/
switch (a->kind)
{
case AEXPR_BETWEEN:
args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
aexpr, bexpr,
a->location),
makeSimpleA_Expr(AEXPR_OP, "<=",
copyObject(aexpr), cexpr,
a->location));
result = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
break;
case AEXPR_NOT_BETWEEN:
args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
aexpr, bexpr,
a->location),
makeSimpleA_Expr(AEXPR_OP, ">",
copyObject(aexpr), cexpr,
a->location));
result = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
break;
case AEXPR_BETWEEN_SYM:
args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
aexpr, bexpr,
a->location),
makeSimpleA_Expr(AEXPR_OP, "<=",
copyObject(aexpr), cexpr,
a->location));
sub1 = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
copyObject(aexpr), copyObject(cexpr),
a->location),
makeSimpleA_Expr(AEXPR_OP, "<=",
copyObject(aexpr), copyObject(bexpr),
a->location));
sub2 = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
args = list_make2(sub1, sub2);
result = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
break;
case AEXPR_NOT_BETWEEN_SYM:
args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
aexpr, bexpr,
a->location),
makeSimpleA_Expr(AEXPR_OP, ">",
copyObject(aexpr), cexpr,
a->location));
sub1 = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
copyObject(aexpr), copyObject(cexpr),
a->location),
makeSimpleA_Expr(AEXPR_OP, ">",
copyObject(aexpr), copyObject(bexpr),
a->location));
sub2 = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
args = list_make2(sub1, sub2);
result = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
break;
default:
elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
result = NULL; /* keep compiler quiet */
break;
}
return transformExprRecurse(pstate, result);
}
static Node *
transformBoolExpr(ParseState *pstate, BoolExpr *a)
{
List *args = NIL;
const char *opname;
ListCell *lc;
switch (a->boolop)
{
case AND_EXPR:
opname = "AND";
break;
case OR_EXPR:
opname = "OR";
break;
case NOT_EXPR:
opname = "NOT";
break;
default:
elog(ERROR, "unrecognized boolop: %d", (int) a->boolop);
opname = NULL; /* keep compiler quiet */
break;
}
foreach(lc, a->args)
{
Node *arg = (Node *) lfirst(lc);
arg = transformExprRecurse(pstate, arg);
arg = coerce_to_boolean(pstate, arg, opname);
args = lappend(args, arg);
}
return (Node *) makeBoolExpr(a->boolop, args, a->location);
}
static Node *
transformFuncCall(ParseState *pstate, FuncCall *fn)
{
Node *last_srf = pstate->p_last_srf;
List *targs;
ListCell *args;
/* Transform the list of arguments ... */
targs = NIL;
foreach(args, fn->args)
{
targs = lappend(targs, transformExprRecurse(pstate,
(Node *) lfirst(args)));
}
/*
* When WITHIN GROUP is used, we treat its ORDER BY expressions as
* additional arguments to the function, for purposes of function lookup
* and argument type coercion. So, transform each such expression and add
* them to the targs list. We don't explicitly mark where each argument
* came from, but ParseFuncOrColumn can tell what's what by reference to
* list_length(fn->agg_order).
*/
if (fn->agg_within_group)
{
Assert(fn->agg_order != NIL);
foreach(args, fn->agg_order)
{
SortBy *arg = (SortBy *) lfirst(args);
targs = lappend(targs, transformExpr(pstate, arg->node,
EXPR_KIND_ORDER_BY));
}
}
/* ... and hand off to ParseFuncOrColumn */
return ParseFuncOrColumn(pstate,
fn->funcname,
targs,
last_srf,
fn,
false,
fn->location);
}
static Node *
transformMultiAssignRef(ParseState *pstate, MultiAssignRef *maref)
{
SubLink *sublink;
RowExpr *rexpr;
Query *qtree;
TargetEntry *tle;
/* We should only see this in first-stage processing of UPDATE tlists */
Assert(pstate->p_expr_kind == EXPR_KIND_UPDATE_SOURCE);
/* We only need to transform the source if this is the first column */
if (maref->colno == 1)
{
/*
* For now, we only allow EXPR SubLinks and RowExprs as the source of
* an UPDATE multiassignment. This is sufficient to cover interesting
* cases; at worst, someone would have to write (SELECT * FROM expr)
* to expand a composite-returning expression of another form.
*/
if (IsA(maref->source, SubLink) &&
((SubLink *) maref->source)->subLinkType == EXPR_SUBLINK)
{
/* Relabel it as a MULTIEXPR_SUBLINK */
sublink = (SubLink *) maref->source;
sublink->subLinkType = MULTIEXPR_SUBLINK;
/* And transform it */
sublink = (SubLink *) transformExprRecurse(pstate,
(Node *) sublink);
qtree = castNode(Query, sublink->subselect);
/* Check subquery returns required number of columns */
if (count_nonjunk_tlist_entries(qtree->targetList) != maref->ncolumns)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("number of columns does not match number of values"),
parser_errposition(pstate, sublink->location)));
/*
* Build a resjunk tlist item containing the MULTIEXPR SubLink,
* and add it to pstate->p_multiassign_exprs, whence it will later
* get appended to the completed targetlist. We needn't worry
* about selecting a resno for it; transformUpdateStmt will do
* that.
*/
tle = makeTargetEntry((Expr *) sublink, 0, NULL, true);
pstate->p_multiassign_exprs = lappend(pstate->p_multiassign_exprs,
tle);
/*
* Assign a unique-within-this-targetlist ID to the MULTIEXPR
* SubLink. We can just use its position in the
* p_multiassign_exprs list.
*/
sublink->subLinkId = list_length(pstate->p_multiassign_exprs);
}
else if (IsA(maref->source, RowExpr))
{
/* Transform the RowExpr, allowing SetToDefault items */
rexpr = (RowExpr *) transformRowExpr(pstate,
(RowExpr *) maref->source,
true);
/* Check it returns required number of columns */
if (list_length(rexpr->args) != maref->ncolumns)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("number of columns does not match number of values"),
parser_errposition(pstate, rexpr->location)));
/*
* Temporarily append it to p_multiassign_exprs, so we can get it
* back when we come back here for additional columns.
*/
tle = makeTargetEntry((Expr *) rexpr, 0, NULL, true);
pstate->p_multiassign_exprs = lappend(pstate->p_multiassign_exprs,
tle);
}
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("source for a multiple-column UPDATE item must be a sub-SELECT or ROW() expression"),
parser_errposition(pstate, exprLocation(maref->source))));
}
else
{
/*
* Second or later column in a multiassignment. Re-fetch the
* transformed SubLink or RowExpr, which we assume is still the last
* entry in p_multiassign_exprs.
*/
Assert(pstate->p_multiassign_exprs != NIL);
tle = (TargetEntry *) llast(pstate->p_multiassign_exprs);
}
/*
* Emit the appropriate output expression for the current column
*/
if (IsA(tle->expr, SubLink))
{
Param *param;
sublink = (SubLink *) tle->expr;
Assert(sublink->subLinkType == MULTIEXPR_SUBLINK);
qtree = castNode(Query, sublink->subselect);
/* Build a Param representing the current subquery output column */
tle = (TargetEntry *) list_nth(qtree->targetList, maref->colno - 1);
Assert(!tle->resjunk);
param = makeNode(Param);
param->paramkind = PARAM_MULTIEXPR;
param->paramid = (sublink->subLinkId << 16) | maref->colno;
param->paramtype = exprType((Node *) tle->expr);
param->paramtypmod = exprTypmod((Node *) tle->expr);
param->paramcollid = exprCollation((Node *) tle->expr);
param->location = exprLocation((Node *) tle->expr);
return (Node *) param;
}
if (IsA(tle->expr, RowExpr))
{
Node *result;
rexpr = (RowExpr *) tle->expr;
/* Just extract and return the next element of the RowExpr */
result = (Node *) list_nth(rexpr->args, maref->colno - 1);
/*
* If we're at the last column, delete the RowExpr from
* p_multiassign_exprs; we don't need it anymore, and don't want it in
* the finished UPDATE tlist. We assume this is still the last entry
* in p_multiassign_exprs.
*/
if (maref->colno == maref->ncolumns)
pstate->p_multiassign_exprs =
list_delete_last(pstate->p_multiassign_exprs);
return result;
}
elog(ERROR, "unexpected expr type in multiassign list");
return NULL; /* keep compiler quiet */
}
static Node *
transformCaseExpr(ParseState *pstate, CaseExpr *c)
{
CaseExpr *newc = makeNode(CaseExpr);
Node *last_srf = pstate->p_last_srf;
Node *arg;
CaseTestExpr *placeholder;
List *newargs;
List *resultexprs;
ListCell *l;
Node *defresult;
Oid ptype;
/* transform the test expression, if any */
arg = transformExprRecurse(pstate, (Node *) c->arg);
/* generate placeholder for test expression */
if (arg)
{
/*
* If test expression is an untyped literal, force it to text. We have
* to do something now because we won't be able to do this coercion on
* the placeholder. This is not as flexible as what was done in 7.4
* and before, but it's good enough to handle the sort of silly coding
* commonly seen.
*/
if (exprType(arg) == UNKNOWNOID)
arg = coerce_to_common_type(pstate, arg, TEXTOID, "CASE");
/*
* Run collation assignment on the test expression so that we know
* what collation to mark the placeholder with. In principle we could
* leave it to parse_collate.c to do that later, but propagating the
* result to the CaseTestExpr would be unnecessarily complicated.
*/
assign_expr_collations(pstate, arg);
placeholder = makeNode(CaseTestExpr);
placeholder->typeId = exprType(arg);
placeholder->typeMod = exprTypmod(arg);
placeholder->collation = exprCollation(arg);
}
else
placeholder = NULL;
newc->arg = (Expr *) arg;
/* transform the list of arguments */
newargs = NIL;
resultexprs = NIL;
foreach(l, c->args)
{
CaseWhen *w = lfirst_node(CaseWhen, l);
CaseWhen *neww = makeNode(CaseWhen);
Node *warg;
warg = (Node *) w->expr;
if (placeholder)
{
/* shorthand form was specified, so expand... */
warg = (Node *) makeSimpleA_Expr(AEXPR_OP, "=",
(Node *) placeholder,
warg,
w->location);
}
neww->expr = (Expr *) transformExprRecurse(pstate, warg);
neww->expr = (Expr *) coerce_to_boolean(pstate,
(Node *) neww->expr,
"CASE/WHEN");
warg = (Node *) w->result;
neww->result = (Expr *) transformExprRecurse(pstate, warg);
neww->location = w->location;
newargs = lappend(newargs, neww);
resultexprs = lappend(resultexprs, neww->result);
}
newc->args = newargs;
/* transform the default clause */
defresult = (Node *) c->defresult;
if (defresult == NULL)
{
A_Const *n = makeNode(A_Const);
n->isnull = true;
n->location = -1;
defresult = (Node *) n;
}
newc->defresult = (Expr *) transformExprRecurse(pstate, defresult);
/*
* Note: default result is considered the most significant type in
* determining preferred type. This is how the code worked before, but it
* seems a little bogus to me --- tgl
*/
resultexprs = lcons(newc->defresult, resultexprs);
ptype = select_common_type(pstate, resultexprs, "CASE", NULL);
Assert(OidIsValid(ptype));
newc->casetype = ptype;
/* casecollid will be set by parse_collate.c */
/* Convert default result clause, if necessary */
newc->defresult = (Expr *)
coerce_to_common_type(pstate,
(Node *) newc->defresult,
ptype,
"CASE/ELSE");
/* Convert when-clause results, if necessary */
foreach(l, newc->args)
{
CaseWhen *w = (CaseWhen *) lfirst(l);
w->result = (Expr *)
coerce_to_common_type(pstate,
(Node *) w->result,
ptype,
"CASE/WHEN");
}
/* if any subexpression contained a SRF, complain */
if (pstate->p_last_srf != last_srf)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s is name of a SQL construct, eg GROUP BY */
errmsg("set-returning functions are not allowed in %s",
"CASE"),
errhint("You might be able to move the set-returning function into a LATERAL FROM item."),
parser_errposition(pstate,
exprLocation(pstate->p_last_srf))));
newc->location = c->location;
return (Node *) newc;
}
static Node *
transformSubLink(ParseState *pstate, SubLink *sublink)
{
Node *result = (Node *) sublink;
Query *qtree;
const char *err;
/*
* Check to see if the sublink is in an invalid place within the query. We
* allow sublinks everywhere in SELECT/INSERT/UPDATE/DELETE/MERGE, but
* generally not in utility statements.
*/
err = NULL;
switch (pstate->p_expr_kind)
{
case EXPR_KIND_NONE:
Assert(false); /* can't happen */
break;
case EXPR_KIND_OTHER:
/* Accept sublink here; caller must throw error if wanted */
break;
case EXPR_KIND_JOIN_ON:
case EXPR_KIND_JOIN_USING:
case EXPR_KIND_FROM_SUBSELECT:
case EXPR_KIND_FROM_FUNCTION:
case EXPR_KIND_WHERE:
case EXPR_KIND_POLICY:
case EXPR_KIND_HAVING:
case EXPR_KIND_FILTER:
case EXPR_KIND_WINDOW_PARTITION:
case EXPR_KIND_WINDOW_ORDER:
case EXPR_KIND_WINDOW_FRAME_RANGE:
case EXPR_KIND_WINDOW_FRAME_ROWS:
case EXPR_KIND_WINDOW_FRAME_GROUPS:
case EXPR_KIND_SELECT_TARGET:
case EXPR_KIND_INSERT_TARGET:
case EXPR_KIND_UPDATE_SOURCE:
case EXPR_KIND_UPDATE_TARGET:
case EXPR_KIND_MERGE_WHEN:
case EXPR_KIND_GROUP_BY:
case EXPR_KIND_ORDER_BY:
case EXPR_KIND_DISTINCT_ON:
case EXPR_KIND_LIMIT:
case EXPR_KIND_OFFSET:
case EXPR_KIND_RETURNING:
case EXPR_KIND_VALUES:
case EXPR_KIND_VALUES_SINGLE:
case EXPR_KIND_CYCLE_MARK:
/* okay */
break;
case EXPR_KIND_CHECK_CONSTRAINT:
case EXPR_KIND_DOMAIN_CHECK:
err = _("cannot use subquery in check constraint");
break;
case EXPR_KIND_COLUMN_DEFAULT:
case EXPR_KIND_FUNCTION_DEFAULT:
err = _("cannot use subquery in DEFAULT expression");
break;
case EXPR_KIND_INDEX_EXPRESSION:
err = _("cannot use subquery in index expression");
break;
case EXPR_KIND_INDEX_PREDICATE:
err = _("cannot use subquery in index predicate");
break;
case EXPR_KIND_STATS_EXPRESSION:
err = _("cannot use subquery in statistics expression");
break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
err = _("cannot use subquery in transform expression");
break;
case EXPR_KIND_EXECUTE_PARAMETER:
err = _("cannot use subquery in EXECUTE parameter");
break;
case EXPR_KIND_TRIGGER_WHEN:
err = _("cannot use subquery in trigger WHEN condition");
break;
case EXPR_KIND_PARTITION_BOUND:
err = _("cannot use subquery in partition bound");
break;
case EXPR_KIND_PARTITION_EXPRESSION:
err = _("cannot use subquery in partition key expression");
break;
case EXPR_KIND_CALL_ARGUMENT:
err = _("cannot use subquery in CALL argument");
break;
case EXPR_KIND_COPY_WHERE:
err = _("cannot use subquery in COPY FROM WHERE condition");
break;
case EXPR_KIND_GENERATED_COLUMN:
err = _("cannot use subquery in column generation expression");
break;
/*
* There is intentionally no default: case here, so that the
* compiler will warn if we add a new ParseExprKind without
* extending this switch. If we do see an unrecognized value at
* runtime, the behavior will be the same as for EXPR_KIND_OTHER,
* which is sane anyway.
*/
}
if (err)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg_internal("%s", err),
parser_errposition(pstate, sublink->location)));
pstate->p_hasSubLinks = true;
/*
* OK, let's transform the sub-SELECT.
*/
qtree = parse_sub_analyze(sublink->subselect, pstate, NULL, false, true);
/*
* Check that we got a SELECT. Anything else should be impossible given
* restrictions of the grammar, but check anyway.
*/
if (!IsA(qtree, Query) ||
qtree->commandType != CMD_SELECT)
elog(ERROR, "unexpected non-SELECT command in SubLink");
sublink->subselect = (Node *) qtree;
if (sublink->subLinkType == EXISTS_SUBLINK)
{
/*
* EXISTS needs no test expression or combining operator. These fields
* should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
/*
* Make sure the subselect delivers a single column (ignoring resjunk
* targets).
*/
if (count_nonjunk_tlist_entries(qtree->targetList) != 1)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return only one column"),
parser_errposition(pstate, sublink->location)));
/*
* EXPR and ARRAY need no test expression or combining operator. These
* fields should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else if (sublink->subLinkType == MULTIEXPR_SUBLINK)
{
/* Same as EXPR case, except no restriction on number of columns */
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else
{
/* ALL, ANY, or ROWCOMPARE: generate row-comparing expression */
Node *lefthand;
List *left_list;
List *right_list;
ListCell *l;
/*
* If the source was "x IN (select)", convert to "x = ANY (select)".
*/
if (sublink->operName == NIL)
sublink->operName = list_make1(makeString("="));
/*
* Transform lefthand expression, and convert to a list
*/
lefthand = transformExprRecurse(pstate, sublink->testexpr);
if (lefthand && IsA(lefthand, RowExpr))
left_list = ((RowExpr *) lefthand)->args;
else
left_list = list_make1(lefthand);
/*
* Build a list of PARAM_SUBLINK nodes representing the output columns
* of the subquery.
*/
right_list = NIL;
foreach(l, qtree->targetList)
{
TargetEntry *tent = (TargetEntry *) lfirst(l);
Param *param;
if (tent->resjunk)
continue;
param = makeNode(Param);
param->paramkind = PARAM_SUBLINK;
param->paramid = tent->resno;
param->paramtype = exprType((Node *) tent->expr);
param->paramtypmod = exprTypmod((Node *) tent->expr);
param->paramcollid = exprCollation((Node *) tent->expr);
param->location = -1;
right_list = lappend(right_list, param);
}
/*
* We could rely on make_row_comparison_op to complain if the list
* lengths differ, but we prefer to generate a more specific error
* message.
*/
if (list_length(left_list) < list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too many columns"),
parser_errposition(pstate, sublink->location)));
if (list_length(left_list) > list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too few columns"),
parser_errposition(pstate, sublink->location)));
/*
* Identify the combining operator(s) and generate a suitable
* row-comparison expression.
*/
sublink->testexpr = make_row_comparison_op(pstate,
sublink->operName,
left_list,
right_list,
sublink->location);
}
return result;
}
/*
* transformArrayExpr
*
* If the caller specifies the target type, the resulting array will
* be of exactly that type. Otherwise we try to infer a common type
* for the elements using select_common_type().
*/
static Node *
transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
Oid array_type, Oid element_type, int32 typmod)
{
ArrayExpr *newa = makeNode(ArrayExpr);
List *newelems = NIL;
List *newcoercedelems = NIL;
ListCell *element;
Oid coerce_type;
bool coerce_hard;
/*
* Transform the element expressions
*
* Assume that the array is one-dimensional unless we find an array-type
* element expression.
*/
newa->multidims = false;
foreach(element, a->elements)
{
Node *e = (Node *) lfirst(element);
Node *newe;
/*
* If an element is itself an A_ArrayExpr, recurse directly so that we
* can pass down any target type we were given.
*/
if (IsA(e, A_ArrayExpr))
{
newe = transformArrayExpr(pstate,
(A_ArrayExpr *) e,
array_type,
element_type,
typmod);
/* we certainly have an array here */
Assert(array_type == InvalidOid || array_type == exprType(newe));
newa->multidims = true;
}
else
{
newe = transformExprRecurse(pstate, e);
/*
* Check for sub-array expressions, if we haven't already found
* one.
*/
if (!newa->multidims && type_is_array(exprType(newe)))
newa->multidims = true;
}
newelems = lappend(newelems, newe);
}
/*
* Select a target type for the elements.
*
* If we haven't been given a target array type, we must try to deduce a
* common type based on the types of the individual elements present.
*/
if (OidIsValid(array_type))
{
/* Caller must ensure array_type matches element_type */
Assert(OidIsValid(element_type));
coerce_type = (newa->multidims ? array_type : element_type);
coerce_hard = true;
}
else
{
/* Can't handle an empty array without a target type */
if (newelems == NIL)
ereport(ERROR,
(errcode(ERRCODE_INDETERMINATE_DATATYPE),
errmsg("cannot determine type of empty array"),
errhint("Explicitly cast to the desired type, "
"for example ARRAY[]::integer[]."),
parser_errposition(pstate, a->location)));
/* Select a common type for the elements */
coerce_type = select_common_type(pstate, newelems, "ARRAY", NULL);
if (newa->multidims)
{
array_type = coerce_type;
element_type = get_element_type(array_type);
if (!OidIsValid(element_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find element type for data type %s",
format_type_be(array_type)),
parser_errposition(pstate, a->location)));
}
else
{
element_type = coerce_type;
array_type = get_array_type(element_type);
if (!OidIsValid(array_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(element_type)),
parser_errposition(pstate, a->location)));
}
coerce_hard = false;
}
/*
* Coerce elements to target type
*
* If the array has been explicitly cast, then the elements are in turn
* explicitly coerced.
*
* If the array's type was merely derived from the common type of its
* elements, then the elements are implicitly coerced to the common type.
* This is consistent with other uses of select_common_type().
*/
foreach(element, newelems)
{
Node *e = (Node *) lfirst(element);
Node *newe;
if (coerce_hard)
{
newe = coerce_to_target_type(pstate, e,
exprType(e),
coerce_type,
typmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
-1);
if (newe == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(exprType(e)),
format_type_be(coerce_type)),
parser_errposition(pstate, exprLocation(e))));
}
else
newe = coerce_to_common_type(pstate, e,
coerce_type,
"ARRAY");
newcoercedelems = lappend(newcoercedelems, newe);
}
newa->array_typeid = array_type;
/* array_collid will be set by parse_collate.c */
newa->element_typeid = element_type;
newa->elements = newcoercedelems;
newa->location = a->location;
return (Node *) newa;
}
static Node *
transformRowExpr(ParseState *pstate, RowExpr *r, bool allowDefault)
{
RowExpr *newr;
char fname[16];
int fnum;
newr = makeNode(RowExpr);
/* Transform the field expressions */
newr->args = transformExpressionList(pstate, r->args,
pstate->p_expr_kind, allowDefault);
/* Disallow more columns than will fit in a tuple */
if (list_length(newr->args) > MaxTupleAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("ROW expressions can have at most %d entries",
MaxTupleAttributeNumber),
parser_errposition(pstate, r->location)));
/* Barring later casting, we consider the type RECORD */
newr->row_typeid = RECORDOID;
newr->row_format = COERCE_IMPLICIT_CAST;
/* ROW() has anonymous columns, so invent some field names */
newr->colnames = NIL;
for (fnum = 1; fnum <= list_length(newr->args); fnum++)
{
snprintf(fname, sizeof(fname), "f%d", fnum);
newr->colnames = lappend(newr->colnames, makeString(pstrdup(fname)));
}
newr->location = r->location;
return (Node *) newr;
}
static Node *
transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
{
CoalesceExpr *newc = makeNode(CoalesceExpr);
Node *last_srf = pstate->p_last_srf;
List *newargs = NIL;
List *newcoercedargs = NIL;
ListCell *args;
foreach(args, c->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExprRecurse(pstate, e);
newargs = lappend(newargs, newe);
}
newc->coalescetype = select_common_type(pstate, newargs, "COALESCE", NULL);
/* coalescecollid will be set by parse_collate.c */
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newc->coalescetype,
"COALESCE");
newcoercedargs = lappend(newcoercedargs, newe);
}
/* if any subexpression contained a SRF, complain */
if (pstate->p_last_srf != last_srf)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s is name of a SQL construct, eg GROUP BY */
errmsg("set-returning functions are not allowed in %s",
"COALESCE"),
errhint("You might be able to move the set-returning function into a LATERAL FROM item."),
parser_errposition(pstate,
exprLocation(pstate->p_last_srf))));
newc->args = newcoercedargs;
newc->location = c->location;
return (Node *) newc;
}
static Node *
transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
{
MinMaxExpr *newm = makeNode(MinMaxExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
const char *funcname = (m->op == IS_GREATEST) ? "GREATEST" : "LEAST";
ListCell *args;
newm->op = m->op;
foreach(args, m->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExprRecurse(pstate, e);
newargs = lappend(newargs, newe);
}
newm->minmaxtype = select_common_type(pstate, newargs, funcname, NULL);
/* minmaxcollid and inputcollid will be set by parse_collate.c */
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newm->minmaxtype,
funcname);
newcoercedargs = lappend(newcoercedargs, newe);
}
newm->args = newcoercedargs;
newm->location = m->location;
return (Node *) newm;
}
static Node *
transformSQLValueFunction(ParseState *pstate, SQLValueFunction *svf)
{
/*
* All we need to do is insert the correct result type and (where needed)
* validate the typmod, so we just modify the node in-place.
*/
switch (svf->op)
{
case SVFOP_CURRENT_DATE:
svf->type = DATEOID;
break;
case SVFOP_CURRENT_TIME:
svf->type = TIMETZOID;
break;
case SVFOP_CURRENT_TIME_N:
svf->type = TIMETZOID;
svf->typmod = anytime_typmod_check(true, svf->typmod);
break;
case SVFOP_CURRENT_TIMESTAMP:
svf->type = TIMESTAMPTZOID;
break;
case SVFOP_CURRENT_TIMESTAMP_N:
svf->type = TIMESTAMPTZOID;
svf->typmod = anytimestamp_typmod_check(true, svf->typmod);
break;
case SVFOP_LOCALTIME:
svf->type = TIMEOID;
break;
case SVFOP_LOCALTIME_N:
svf->type = TIMEOID;
svf->typmod = anytime_typmod_check(false, svf->typmod);
break;
case SVFOP_LOCALTIMESTAMP:
svf->type = TIMESTAMPOID;
break;
case SVFOP_LOCALTIMESTAMP_N:
svf->type = TIMESTAMPOID;
svf->typmod = anytimestamp_typmod_check(false, svf->typmod);
break;
case SVFOP_CURRENT_ROLE:
case SVFOP_CURRENT_USER:
case SVFOP_USER:
case SVFOP_SESSION_USER:
case SVFOP_CURRENT_CATALOG:
case SVFOP_CURRENT_SCHEMA:
svf->type = NAMEOID;
break;
}
return (Node *) svf;
}
static Node *
transformXmlExpr(ParseState *pstate, XmlExpr *x)
{
XmlExpr *newx;
ListCell *lc;
int i;
newx = makeNode(XmlExpr);
newx->op = x->op;
if (x->name)
newx->name = map_sql_identifier_to_xml_name(x->name, false, false);
else
newx->name = NULL;
newx->xmloption = x->xmloption;
newx->type = XMLOID; /* this just marks the node as transformed */
newx->typmod = -1;
newx->location = x->location;
/*
* gram.y built the named args as a list of ResTarget. Transform each,
* and break the names out as a separate list.
*/
newx->named_args = NIL;
newx->arg_names = NIL;
foreach(lc, x->named_args)
{
ResTarget *r = lfirst_node(ResTarget, lc);
Node *expr;
char *argname;
expr = transformExprRecurse(pstate, r->val);
if (r->name)
argname = map_sql_identifier_to_xml_name(r->name, false, false);
else if (IsA(r->val, ColumnRef))
argname = map_sql_identifier_to_xml_name(FigureColname(r->val),
true, false);
else
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
x->op == IS_XMLELEMENT
? errmsg("unnamed XML attribute value must be a column reference")
: errmsg("unnamed XML element value must be a column reference"),
parser_errposition(pstate, r->location)));
argname = NULL; /* keep compiler quiet */
}
/* reject duplicate argnames in XMLELEMENT only */
if (x->op == IS_XMLELEMENT)
{
ListCell *lc2;
foreach(lc2, newx->arg_names)
{
if (strcmp(argname, strVal(lfirst(lc2))) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("XML attribute name \"%s\" appears more than once",
argname),
parser_errposition(pstate, r->location)));
}
}
newx->named_args = lappend(newx->named_args, expr);
newx->arg_names = lappend(newx->arg_names, makeString(argname));
}
/* The other arguments are of varying types depending on the function */
newx->args = NIL;
i = 0;
foreach(lc, x->args)
{
Node *e = (Node *) lfirst(lc);
Node *newe;
newe = transformExprRecurse(pstate, e);
switch (x->op)
{
case IS_XMLCONCAT:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLCONCAT");
break;
case IS_XMLELEMENT:
/* no coercion necessary */
break;
case IS_XMLFOREST:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLFOREST");
break;
case IS_XMLPARSE:
if (i == 0)
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLPARSE");
else
newe = coerce_to_boolean(pstate, newe, "XMLPARSE");
break;
case IS_XMLPI:
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLPI");
break;
case IS_XMLROOT:
if (i == 0)
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLROOT");
else if (i == 1)
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLROOT");
else
newe = coerce_to_specific_type(pstate, newe, INT4OID,
"XMLROOT");
break;
case IS_XMLSERIALIZE:
/* not handled here */
Assert(false);
break;
case IS_DOCUMENT:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"IS DOCUMENT");
break;
}
newx->args = lappend(newx->args, newe);
i++;
}
return (Node *) newx;
}
static Node *
transformXmlSerialize(ParseState *pstate, XmlSerialize *xs)
{
Node *result;
XmlExpr *xexpr;
Oid targetType;
int32 targetTypmod;
xexpr = makeNode(XmlExpr);
xexpr->op = IS_XMLSERIALIZE;
xexpr->args = list_make1(coerce_to_specific_type(pstate,
transformExprRecurse(pstate, xs->expr),
XMLOID,
"XMLSERIALIZE"));
typenameTypeIdAndMod(pstate, xs->typeName, &targetType, &targetTypmod);
xexpr->xmloption = xs->xmloption;
xexpr->indent = xs->indent;
xexpr->location = xs->location;
/* We actually only need these to be able to parse back the expression. */
xexpr->type = targetType;
xexpr->typmod = targetTypmod;
/*
* The actual target type is determined this way. SQL allows char and
* varchar as target types. We allow anything that can be cast implicitly
* from text. This way, user-defined text-like data types automatically
* fit in.
*/
result = coerce_to_target_type(pstate, (Node *) xexpr,
TEXTOID, targetType, targetTypmod,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
-1);
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast XMLSERIALIZE result to %s",
format_type_be(targetType)),
parser_errposition(pstate, xexpr->location)));
return result;
}
static Node *
transformBooleanTest(ParseState *pstate, BooleanTest *b)
{
const char *clausename;
switch (b->booltesttype)
{
case IS_TRUE:
clausename = "IS TRUE";
break;
case IS_NOT_TRUE:
clausename = "IS NOT TRUE";
break;
case IS_FALSE:
clausename = "IS FALSE";
break;
case IS_NOT_FALSE:
clausename = "IS NOT FALSE";
break;
case IS_UNKNOWN:
clausename = "IS UNKNOWN";
break;
case IS_NOT_UNKNOWN:
clausename = "IS NOT UNKNOWN";
break;
default:
elog(ERROR, "unrecognized booltesttype: %d",
(int) b->booltesttype);
clausename = NULL; /* keep compiler quiet */
}
b->arg = (Expr *) transformExprRecurse(pstate, (Node *) b->arg);
b->arg = (Expr *) coerce_to_boolean(pstate,
(Node *) b->arg,
clausename);
return (Node *) b;
}
static Node *
transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr)
{
/* CURRENT OF can only appear at top level of UPDATE/DELETE */
Assert(pstate->p_target_nsitem != NULL);
cexpr->cvarno = pstate->p_target_nsitem->p_rtindex;
/*
* Check to see if the cursor name matches a parameter of type REFCURSOR.
* If so, replace the raw name reference with a parameter reference. (This
* is a hack for the convenience of plpgsql.)
*/
if (cexpr->cursor_name != NULL) /* in case already transformed */
{
ColumnRef *cref = makeNode(ColumnRef);
Node *node = NULL;
/* Build an unqualified ColumnRef with the given name */
cref->fields = list_make1(makeString(cexpr->cursor_name));
cref->location = -1;
/* See if there is a translation available from a parser hook */
if (pstate->p_pre_columnref_hook != NULL)
node = pstate->p_pre_columnref_hook(pstate, cref);
if (node == NULL && pstate->p_post_columnref_hook != NULL)
node = pstate->p_post_columnref_hook(pstate, cref, NULL);
/*
* XXX Should we throw an error if we get a translation that isn't a
* refcursor Param? For now it seems best to silently ignore false
* matches.
*/
if (node != NULL && IsA(node, Param))
{
Param *p = (Param *) node;
if (p->paramkind == PARAM_EXTERN &&
p->paramtype == REFCURSOROID)
{
/* Matches, so convert CURRENT OF to a param reference */
cexpr->cursor_name = NULL;
cexpr->cursor_param = p->paramid;
}
}
}
return (Node *) cexpr;
}
/*
* Construct a whole-row reference to represent the notation "relation.*".
*/
static Node *
transformWholeRowRef(ParseState *pstate, ParseNamespaceItem *nsitem,
int sublevels_up, int location)
{
/*
* Build the appropriate referencing node. Normally this can be a
* whole-row Var, but if the nsitem is a JOIN USING alias then it contains
* only a subset of the columns of the underlying join RTE, so that will
* not work. Instead we immediately expand the reference into a RowExpr.
* Since the JOIN USING's common columns are fully determined at this
* point, there seems no harm in expanding it now rather than during
* planning.
*
* Note that if the RTE is a function returning scalar, we create just a
* plain reference to the function value, not a composite containing a
* single column. This is pretty inconsistent at first sight, but it's
* what we've done historically. One argument for it is that "rel" and
* "rel.*" mean the same thing for composite relations, so why not for
* scalar functions...
*/
if (nsitem->p_names == nsitem->p_rte->eref)
{
Var *result;
result = makeWholeRowVar(nsitem->p_rte, nsitem->p_rtindex,
sublevels_up, true);
/* location is not filled in by makeWholeRowVar */
result->location = location;
/* mark Var if it's nulled by any outer joins */
markNullableIfNeeded(pstate, result);
/* mark relation as requiring whole-row SELECT access */
markVarForSelectPriv(pstate, result);
return (Node *) result;
}
else
{
RowExpr *rowexpr;
List *fields;
/*
* We want only as many columns as are listed in p_names->colnames,
* and we should use those names not whatever possibly-aliased names
* are in the RTE. We needn't worry about marking the RTE for SELECT
* access, as the common columns are surely so marked already.
*/
expandRTE(nsitem->p_rte, nsitem->p_rtindex,
sublevels_up, location, false,
NULL, &fields);
rowexpr = makeNode(RowExpr);
rowexpr->args = list_truncate(fields,
list_length(nsitem->p_names->colnames));
rowexpr->row_typeid = RECORDOID;
rowexpr->row_format = COERCE_IMPLICIT_CAST;
rowexpr->colnames = copyObject(nsitem->p_names->colnames);
rowexpr->location = location;
/* XXX we ought to mark the row as possibly nullable */
return (Node *) rowexpr;
}
}
/*
* Handle an explicit CAST construct.
*
* Transform the argument, look up the type name, and apply any necessary
* coercion function(s).
*/
static Node *
transformTypeCast(ParseState *pstate, TypeCast *tc)
{
Node *result;
Node *arg = tc->arg;
Node *expr;
Oid inputType;
Oid targetType;
int32 targetTypmod;
int location;
/* Look up the type name first */
typenameTypeIdAndMod(pstate, tc->typeName, &targetType, &targetTypmod);
/*
* If the subject of the typecast is an ARRAY[] construct and the target
* type is an array type, we invoke transformArrayExpr() directly so that
* we can pass down the type information. This avoids some cases where
* transformArrayExpr() might not infer the correct type. Otherwise, just
* transform the argument normally.
*/
if (IsA(arg, A_ArrayExpr))
{
Oid targetBaseType;
int32 targetBaseTypmod;
Oid elementType;
/*
* If target is a domain over array, work with the base array type
* here. Below, we'll cast the array type to the domain. In the
* usual case that the target is not a domain, the remaining steps
* will be a no-op.
*/
targetBaseTypmod = targetTypmod;
targetBaseType = getBaseTypeAndTypmod(targetType, &targetBaseTypmod);
elementType = get_element_type(targetBaseType);
if (OidIsValid(elementType))
{
expr = transformArrayExpr(pstate,
(A_ArrayExpr *) arg,
targetBaseType,
elementType,
targetBaseTypmod);
}
else
expr = transformExprRecurse(pstate, arg);
}
else
expr = transformExprRecurse(pstate, arg);
inputType = exprType(expr);
if (inputType == InvalidOid)
return expr; /* do nothing if NULL input */
/*
* Location of the coercion is preferentially the location of the :: or
* CAST symbol, but if there is none then use the location of the type
* name (this can happen in TypeName 'string' syntax, for instance).
*/
location = tc->location;
if (location < 0)
location = tc->typeName->location;
result = coerce_to_target_type(pstate, expr, inputType,
targetType, targetTypmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
location);
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(inputType),
format_type_be(targetType)),
parser_coercion_errposition(pstate, location, expr)));
return result;
}
/*
* Handle an explicit COLLATE clause.
*
* Transform the argument, and look up the collation name.
*/
static Node *
transformCollateClause(ParseState *pstate, CollateClause *c)
{
CollateExpr *newc;
Oid argtype;
newc = makeNode(CollateExpr);
newc->arg = (Expr *) transformExprRecurse(pstate, c->arg);
argtype = exprType((Node *) newc->arg);
/*
* The unknown type is not collatable, but coerce_type() takes care of it
* separately, so we'll let it go here.
*/
if (!type_is_collatable(argtype) && argtype != UNKNOWNOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("collations are not supported by type %s",
format_type_be(argtype)),
parser_errposition(pstate, c->location)));
newc->collOid = LookupCollation(pstate, c->collname, c->location);
newc->location = c->location;
return (Node *) newc;
}
/*
* Transform a "row compare-op row" construct
*
* The inputs are lists of already-transformed expressions.
* As with coerce_type, pstate may be NULL if no special unknown-Param
* processing is wanted.
*
* The output may be a single OpExpr, an AND or OR combination of OpExprs,
* or a RowCompareExpr. In all cases it is guaranteed to return boolean.
* The AND, OR, and RowCompareExpr cases further imply things about the
* behavior of the operators (ie, they behave as =, <>, or < <= > >=).
*/
static Node *
make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location)
{
RowCompareExpr *rcexpr;
RowCompareType rctype;
List *opexprs;
List *opnos;
List *opfamilies;
ListCell *l,
*r;
List **opinfo_lists;
Bitmapset *strats;
int nopers;
int i;
nopers = list_length(largs);
if (nopers != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
parser_errposition(pstate, location)));
/*
* We can't compare zero-length rows because there is no principled basis
* for figuring out what the operator is.
*/
if (nopers == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot compare rows of zero length"),
parser_errposition(pstate, location)));
/*
* Identify all the pairwise operators, using make_op so that behavior is
* the same as in the simple scalar case.
*/
opexprs = NIL;
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
OpExpr *cmp;
cmp = castNode(OpExpr, make_op(pstate, opname, larg, rarg,
pstate->p_last_srf, location));
/*
* We don't use coerce_to_boolean here because we insist on the
* operator yielding boolean directly, not via coercion. If it
* doesn't yield bool it won't be in any index opfamilies...
*/
if (cmp->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must yield type boolean, "
"not type %s",
format_type_be(cmp->opresulttype)),
parser_errposition(pstate, location)));
if (expression_returns_set((Node *) cmp))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must not return a set"),
parser_errposition(pstate, location)));
opexprs = lappend(opexprs, cmp);
}
/*
* If rows are length 1, just return the single operator. In this case we
* don't insist on identifying btree semantics for the operator (but we
* still require it to return boolean).
*/
if (nopers == 1)
return (Node *) linitial(opexprs);
/*
* Now we must determine which row comparison semantics (= <> < <= > >=)
* apply to this set of operators. We look for btree opfamilies
* containing the operators, and see which interpretations (strategy
* numbers) exist for each operator.
*/
opinfo_lists = (List **) palloc(nopers * sizeof(List *));
strats = NULL;
i = 0;
foreach(l, opexprs)
{
Oid opno = ((OpExpr *) lfirst(l))->opno;
Bitmapset *this_strats;
ListCell *j;
opinfo_lists[i] = get_op_btree_interpretation(opno);
/*
* convert strategy numbers into a Bitmapset to make the intersection
* calculation easy.
*/
this_strats = NULL;
foreach(j, opinfo_lists[i])
{
OpBtreeInterpretation *opinfo = lfirst(j);
this_strats = bms_add_member(this_strats, opinfo->strategy);
}
if (i == 0)
strats = this_strats;
else
strats = bms_int_members(strats, this_strats);
i++;
}
/*
* If there are multiple common interpretations, we may use any one of
* them ... this coding arbitrarily picks the lowest btree strategy
* number.
*/
i = bms_next_member(strats, -1);
if (i < 0)
{
/* No common interpretation, so fail */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errhint("Row comparison operators must be associated with btree operator families."),
parser_errposition(pstate, location)));
}
rctype = (RowCompareType) i;
/*
* For = and <> cases, we just combine the pairwise operators with AND or
* OR respectively.
*/
if (rctype == ROWCOMPARE_EQ)
return (Node *) makeBoolExpr(AND_EXPR, opexprs, location);
if (rctype == ROWCOMPARE_NE)
return (Node *) makeBoolExpr(OR_EXPR, opexprs, location);
/*
* Otherwise we need to choose exactly which opfamily to associate with
* each operator.
*/
opfamilies = NIL;
for (i = 0; i < nopers; i++)
{
Oid opfamily = InvalidOid;
ListCell *j;
foreach(j, opinfo_lists[i])
{
OpBtreeInterpretation *opinfo = lfirst(j);
if (opinfo->strategy == rctype)
{
opfamily = opinfo->opfamily_id;
break;
}
}
if (OidIsValid(opfamily))
opfamilies = lappend_oid(opfamilies, opfamily);
else /* should not happen */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errdetail("There are multiple equally-plausible candidates."),
parser_errposition(pstate, location)));
}
/*
* Now deconstruct the OpExprs and create a RowCompareExpr.
*
* Note: can't just reuse the passed largs/rargs lists, because of
* possibility that make_op inserted coercion operations.
*/
opnos = NIL;
largs = NIL;
rargs = NIL;
foreach(l, opexprs)
{
OpExpr *cmp = (OpExpr *) lfirst(l);
opnos = lappend_oid(opnos, cmp->opno);
largs = lappend(largs, linitial(cmp->args));
rargs = lappend(rargs, lsecond(cmp->args));
}
rcexpr = makeNode(RowCompareExpr);
rcexpr->rctype = rctype;
rcexpr->opnos = opnos;
rcexpr->opfamilies = opfamilies;
rcexpr->inputcollids = NIL; /* assign_expr_collations will fix this */
rcexpr->largs = largs;
rcexpr->rargs = rargs;
return (Node *) rcexpr;
}
/*
* Transform a "row IS DISTINCT FROM row" construct
*
* The input RowExprs are already transformed
*/
static Node *
make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow,
int location)
{
Node *result = NULL;
List *largs = lrow->args;
List *rargs = rrow->args;
ListCell *l,
*r;
if (list_length(largs) != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
parser_errposition(pstate, location)));
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
Node *cmp;
cmp = (Node *) make_distinct_op(pstate, opname, larg, rarg, location);
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(OR_EXPR,
list_make2(result, cmp),
location);
}
if (result == NULL)
{
/* zero-length rows? Generate constant FALSE */
result = makeBoolConst(false, false);
}
return result;
}
/*
* make the node for an IS DISTINCT FROM operator
*/
static Expr *
make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree,
int location)
{
Expr *result;
result = make_op(pstate, opname, ltree, rtree,
pstate->p_last_srf, location);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("IS DISTINCT FROM requires = operator to yield boolean"),
parser_errposition(pstate, location)));
if (((OpExpr *) result)->opretset)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
/* translator: %s is name of a SQL construct, eg NULLIF */
errmsg("%s must not return a set", "IS DISTINCT FROM"),
parser_errposition(pstate, location)));
/*
* We rely on DistinctExpr and OpExpr being same struct
*/
NodeSetTag(result, T_DistinctExpr);
return result;
}
/*
* Produce a NullTest node from an IS [NOT] DISTINCT FROM NULL construct
*
* "arg" is the untransformed other argument
*/
static Node *
make_nulltest_from_distinct(ParseState *pstate, A_Expr *distincta, Node *arg)
{
NullTest *nt = makeNode(NullTest);
nt->arg = (Expr *) transformExprRecurse(pstate, arg);
/* the argument can be any type, so don't coerce it */
if (distincta->kind == AEXPR_NOT_DISTINCT)
nt->nulltesttype = IS_NULL;
else
nt->nulltesttype = IS_NOT_NULL;
/* argisrow = false is correct whether or not arg is composite */
nt->argisrow = false;
nt->location = distincta->location;
return (Node *) nt;
}
/*
* Produce a string identifying an expression by kind.
*
* Note: when practical, use a simple SQL keyword for the result. If that
* doesn't work well, check call sites to see whether custom error message
* strings are required.
*/
const char *
ParseExprKindName(ParseExprKind exprKind)
{
switch (exprKind)
{
case EXPR_KIND_NONE:
return "invalid expression context";
case EXPR_KIND_OTHER:
return "extension expression";
case EXPR_KIND_JOIN_ON:
return "JOIN/ON";
case EXPR_KIND_JOIN_USING:
return "JOIN/USING";
case EXPR_KIND_FROM_SUBSELECT:
return "sub-SELECT in FROM";
case EXPR_KIND_FROM_FUNCTION:
return "function in FROM";
case EXPR_KIND_WHERE:
return "WHERE";
case EXPR_KIND_POLICY:
return "POLICY";
case EXPR_KIND_HAVING:
return "HAVING";
case EXPR_KIND_FILTER:
return "FILTER";
case EXPR_KIND_WINDOW_PARTITION:
return "window PARTITION BY";
case EXPR_KIND_WINDOW_ORDER:
return "window ORDER BY";
case EXPR_KIND_WINDOW_FRAME_RANGE:
return "window RANGE";
case EXPR_KIND_WINDOW_FRAME_ROWS:
return "window ROWS";
case EXPR_KIND_WINDOW_FRAME_GROUPS:
return "window GROUPS";
case EXPR_KIND_SELECT_TARGET:
return "SELECT";
case EXPR_KIND_INSERT_TARGET:
return "INSERT";
case EXPR_KIND_UPDATE_SOURCE:
case EXPR_KIND_UPDATE_TARGET:
return "UPDATE";
case EXPR_KIND_MERGE_WHEN:
return "MERGE WHEN";
case EXPR_KIND_GROUP_BY:
return "GROUP BY";
case EXPR_KIND_ORDER_BY:
return "ORDER BY";
case EXPR_KIND_DISTINCT_ON:
return "DISTINCT ON";
case EXPR_KIND_LIMIT:
return "LIMIT";
case EXPR_KIND_OFFSET:
return "OFFSET";
case EXPR_KIND_RETURNING:
return "RETURNING";
case EXPR_KIND_VALUES:
case EXPR_KIND_VALUES_SINGLE:
return "VALUES";
case EXPR_KIND_CHECK_CONSTRAINT:
case EXPR_KIND_DOMAIN_CHECK:
return "CHECK";
case EXPR_KIND_COLUMN_DEFAULT:
case EXPR_KIND_FUNCTION_DEFAULT:
return "DEFAULT";
case EXPR_KIND_INDEX_EXPRESSION:
return "index expression";
case EXPR_KIND_INDEX_PREDICATE:
return "index predicate";
case EXPR_KIND_STATS_EXPRESSION:
return "statistics expression";
case EXPR_KIND_ALTER_COL_TRANSFORM:
return "USING";
case EXPR_KIND_EXECUTE_PARAMETER:
return "EXECUTE";
case EXPR_KIND_TRIGGER_WHEN:
return "WHEN";
case EXPR_KIND_PARTITION_BOUND:
return "partition bound";
case EXPR_KIND_PARTITION_EXPRESSION:
return "PARTITION BY";
case EXPR_KIND_CALL_ARGUMENT:
return "CALL";
case EXPR_KIND_COPY_WHERE:
return "WHERE";
case EXPR_KIND_GENERATED_COLUMN:
return "GENERATED AS";
case EXPR_KIND_CYCLE_MARK:
return "CYCLE";
/*
* There is intentionally no default: case here, so that the
* compiler will warn if we add a new ParseExprKind without
* extending this switch. If we do see an unrecognized value at
* runtime, we'll fall through to the "unrecognized" return.
*/
}
return "unrecognized expression kind";
}
/*
* Make string Const node from JSON encoding name.
*
* UTF8 is default encoding.
*/
static Const *
getJsonEncodingConst(JsonFormat *format)
{
JsonEncoding encoding;
const char *enc;
Name encname = palloc(sizeof(NameData));
if (!format ||
format->format_type == JS_FORMAT_DEFAULT ||
format->encoding == JS_ENC_DEFAULT)
encoding = JS_ENC_UTF8;
else
encoding = format->encoding;
switch (encoding)
{
case JS_ENC_UTF16:
enc = "UTF16";
break;
case JS_ENC_UTF32:
enc = "UTF32";
break;
case JS_ENC_UTF8:
enc = "UTF8";
break;
default:
elog(ERROR, "invalid JSON encoding: %d", encoding);
break;
}
namestrcpy(encname, enc);
return makeConst(NAMEOID, -1, InvalidOid, NAMEDATALEN,
NameGetDatum(encname), false, false);
}
/*
* Make bytea => text conversion using specified JSON format encoding.
*/
static Node *
makeJsonByteaToTextConversion(Node *expr, JsonFormat *format, int location)
{
Const *encoding = getJsonEncodingConst(format);
FuncExpr *fexpr = makeFuncExpr(F_CONVERT_FROM, TEXTOID,
list_make2(expr, encoding),
InvalidOid, InvalidOid,
COERCE_EXPLICIT_CALL);
fexpr->location = location;
return (Node *) fexpr;
}
/*
* Make a CaseTestExpr node.
*/
static Node *
makeCaseTestExpr(Node *expr)
{
CaseTestExpr *placeholder = makeNode(CaseTestExpr);
placeholder->typeId = exprType(expr);
placeholder->typeMod = exprTypmod(expr);
placeholder->collation = exprCollation(expr);
return (Node *) placeholder;
}
/*
* Transform JSON value expression using specified input JSON format or
* default format otherwise.
*/
static Node *
transformJsonValueExpr(ParseState *pstate, JsonValueExpr *ve,
JsonFormatType default_format)
{
Node *expr = transformExprRecurse(pstate, (Node *) ve->raw_expr);
Node *rawexpr;
JsonFormatType format;
Oid exprtype;
int location;
char typcategory;
bool typispreferred;
/*
* Using JSON_VALUE here is slightly bogus: perhaps we need to be passed a
* JsonConstructorType so that we can use one of JSON_OBJECTAGG, etc.
*/
if (exprType(expr) == UNKNOWNOID)
expr = coerce_to_specific_type(pstate, expr, TEXTOID, "JSON_VALUE");
rawexpr = expr;
exprtype = exprType(expr);
location = exprLocation(expr);
get_type_category_preferred(exprtype, &typcategory, &typispreferred);
if (ve->format->format_type != JS_FORMAT_DEFAULT)
{
if (ve->format->encoding != JS_ENC_DEFAULT && exprtype != BYTEAOID)
ereport(ERROR,
errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("JSON ENCODING clause is only allowed for bytea input type"),
parser_errposition(pstate, ve->format->location));
if (exprtype == JSONOID || exprtype == JSONBOID)
{
format = JS_FORMAT_DEFAULT; /* do not format json[b] types */
ereport(WARNING,
errmsg("FORMAT JSON has no effect for json and jsonb types"),
parser_errposition(pstate, ve->format->location));
}
else
format = ve->format->format_type;
}
else if (exprtype == JSONOID || exprtype == JSONBOID)
format = JS_FORMAT_DEFAULT; /* do not format json[b] types */
else
format = default_format;
if (format != JS_FORMAT_DEFAULT)
{
Oid targettype = format == JS_FORMAT_JSONB ? JSONBOID : JSONOID;
Node *orig = makeCaseTestExpr(expr);
Node *coerced;
expr = orig;
if (exprtype != BYTEAOID && typcategory != TYPCATEGORY_STRING)
ereport(ERROR,
errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg(ve->format->format_type == JS_FORMAT_DEFAULT ?
"cannot use non-string types with implicit FORMAT JSON clause" :
"cannot use non-string types with explicit FORMAT JSON clause"),
parser_errposition(pstate, ve->format->location >= 0 ?
ve->format->location : location));
/* Convert encoded JSON text from bytea. */
if (format == JS_FORMAT_JSON && exprtype == BYTEAOID)
{
expr = makeJsonByteaToTextConversion(expr, ve->format, location);
exprtype = TEXTOID;
}
/* Try to coerce to the target type. */
coerced = coerce_to_target_type(pstate, expr, exprtype,
targettype, -1,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
location);
if (!coerced)
{
/* If coercion failed, use to_json()/to_jsonb() functions. */
Oid fnoid = targettype == JSONOID ? F_TO_JSON : F_TO_JSONB;
FuncExpr *fexpr = makeFuncExpr(fnoid, targettype,
list_make1(expr),
InvalidOid, InvalidOid,
COERCE_EXPLICIT_CALL);
fexpr->location = location;
coerced = (Node *) fexpr;
}
if (coerced == orig)
expr = rawexpr;
else
{
ve = copyObject(ve);
ve->raw_expr = (Expr *) rawexpr;
ve->formatted_expr = (Expr *) coerced;
expr = (Node *) ve;
}
}
return expr;
}
/*
* Checks specified output format for its applicability to the target type.
*/
static void
checkJsonOutputFormat(ParseState *pstate, const JsonFormat *format,
Oid targettype, bool allow_format_for_non_strings)
{
if (!allow_format_for_non_strings &&
format->format_type != JS_FORMAT_DEFAULT &&
(targettype != BYTEAOID &&
targettype != JSONOID &&
targettype != JSONBOID))
{
char typcategory;
bool typispreferred;
get_type_category_preferred(targettype, &typcategory, &typispreferred);
if (typcategory != TYPCATEGORY_STRING)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
parser_errposition(pstate, format->location),
errmsg("cannot use JSON format with non-string output types"));
}
if (format->format_type == JS_FORMAT_JSON)
{
JsonEncoding enc = format->encoding != JS_ENC_DEFAULT ?
format->encoding : JS_ENC_UTF8;
if (targettype != BYTEAOID &&
format->encoding != JS_ENC_DEFAULT)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
parser_errposition(pstate, format->location),
errmsg("cannot set JSON encoding for non-bytea output types"));
if (enc != JS_ENC_UTF8)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unsupported JSON encoding"),
errhint("Only UTF8 JSON encoding is supported."),
parser_errposition(pstate, format->location));
}
}
/*
* Transform JSON output clause.
*
* Assigns target type oid and modifier.
* Assigns default format or checks specified format for its applicability to
* the target type.
*/
static JsonReturning *
transformJsonOutput(ParseState *pstate, const JsonOutput *output,
bool allow_format)
{
JsonReturning *ret;
/* if output clause is not specified, make default clause value */
if (!output)
{
ret = makeNode(JsonReturning);
ret->format = makeJsonFormat(JS_FORMAT_DEFAULT, JS_ENC_DEFAULT, -1);
ret->typid = InvalidOid;
ret->typmod = -1;
return ret;
}
ret = copyObject(output->returning);
typenameTypeIdAndMod(pstate, output->typeName, &ret->typid, &ret->typmod);
if (output->typeName->setof)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("returning SETOF types is not supported in SQL/JSON functions"));
if (ret->format->format_type == JS_FORMAT_DEFAULT)
/* assign JSONB format when returning jsonb, or JSON format otherwise */
ret->format->format_type =
ret->typid == JSONBOID ? JS_FORMAT_JSONB : JS_FORMAT_JSON;
else
checkJsonOutputFormat(pstate, ret->format, ret->typid, allow_format);
return ret;
}
/*
* Transform JSON output clause of JSON constructor functions.
*
* Derive RETURNING type, if not specified, from argument types.
*/
static JsonReturning *
transformJsonConstructorOutput(ParseState *pstate, JsonOutput *output,
List *args)
{
JsonReturning *returning = transformJsonOutput(pstate, output, true);
if (!OidIsValid(returning->typid))
{
ListCell *lc;
bool have_jsonb = false;
foreach(lc, args)
{
Node *expr = lfirst(lc);
Oid typid = exprType(expr);
have_jsonb |= typid == JSONBOID;
if (have_jsonb)
break;
}
if (have_jsonb)
{
returning->typid = JSONBOID;
returning->format->format_type = JS_FORMAT_JSONB;
}
else
{
/* XXX TEXT is default by the standard, but we return JSON */
returning->typid = JSONOID;
returning->format->format_type = JS_FORMAT_JSON;
}
returning->typmod = -1;
}
return returning;
}
/*
* Coerce json[b]-valued function expression to the output type.
*/
static Node *
coerceJsonFuncExpr(ParseState *pstate, Node *expr,
const JsonReturning *returning, bool report_error)
{
Node *res;
int location;
Oid exprtype = exprType(expr);
/* if output type is not specified or equals to function type, return */
if (!OidIsValid(returning->typid) || returning->typid == exprtype)
return expr;
location = exprLocation(expr);
if (location < 0)
location = returning->format->location;
/* special case for RETURNING bytea FORMAT json */
if (returning->format->format_type == JS_FORMAT_JSON &&
returning->typid == BYTEAOID)
{
/* encode json text into bytea using pg_convert_to() */
Node *texpr = coerce_to_specific_type(pstate, expr, TEXTOID,
"JSON_FUNCTION");
Const *enc = getJsonEncodingConst(returning->format);
FuncExpr *fexpr = makeFuncExpr(F_CONVERT_TO, BYTEAOID,
list_make2(texpr, enc),
InvalidOid, InvalidOid,
COERCE_EXPLICIT_CALL);
fexpr->location = location;
return (Node *) fexpr;
}
/* try to coerce expression to the output type */
res = coerce_to_target_type(pstate, expr, exprtype,
returning->typid, returning->typmod,
/* XXX throwing errors when casting to char(N) */
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
location);
if (!res && report_error)
ereport(ERROR,
errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(exprtype),
format_type_be(returning->typid)),
parser_coercion_errposition(pstate, location, expr));
return res;
}
/*
* Make a JsonConstructorExpr node.
*/
static Node *
makeJsonConstructorExpr(ParseState *pstate, JsonConstructorType type,
List *args, Expr *fexpr, JsonReturning *returning,
bool unique, bool absent_on_null, int location)
{
JsonConstructorExpr *jsctor = makeNode(JsonConstructorExpr);
Node *placeholder;
Node *coercion;
jsctor->args = args;
jsctor->func = fexpr;
jsctor->type = type;
jsctor->returning = returning;
jsctor->unique = unique;
jsctor->absent_on_null = absent_on_null;
jsctor->location = location;
if (fexpr)
placeholder = makeCaseTestExpr((Node *) fexpr);
else
{
CaseTestExpr *cte = makeNode(CaseTestExpr);
cte->typeId = returning->format->format_type == JS_FORMAT_JSONB ?
JSONBOID : JSONOID;
cte->typeMod = -1;
cte->collation = InvalidOid;
placeholder = (Node *) cte;
}
coercion = coerceJsonFuncExpr(pstate, placeholder, returning, true);
if (coercion != placeholder)
jsctor->coercion = (Expr *) coercion;
return (Node *) jsctor;
}
/*
* Transform JSON_OBJECT() constructor.
*
* JSON_OBJECT() is transformed into json[b]_build_object[_ext]() call
* depending on the output JSON format. The first two arguments of
* json[b]_build_object_ext() are absent_on_null and check_unique.
*
* Then function call result is coerced to the target type.
*/
static Node *
transformJsonObjectConstructor(ParseState *pstate, JsonObjectConstructor *ctor)
{
JsonReturning *returning;
List *args = NIL;
/* transform key-value pairs, if any */
if (ctor->exprs)
{
ListCell *lc;
/* transform and append key-value arguments */
foreach(lc, ctor->exprs)
{
JsonKeyValue *kv = castNode(JsonKeyValue, lfirst(lc));
Node *key = transformExprRecurse(pstate, (Node *) kv->key);
Node *val = transformJsonValueExpr(pstate, kv->value,
JS_FORMAT_DEFAULT);
args = lappend(args, key);
args = lappend(args, val);
}
}
returning = transformJsonConstructorOutput(pstate, ctor->output, args);
return makeJsonConstructorExpr(pstate, JSCTOR_JSON_OBJECT, args, NULL,
returning, ctor->unique,
ctor->absent_on_null, ctor->location);
}
/*
* Transform JSON_ARRAY(query [FORMAT] [RETURNING] [ON NULL]) into
* (SELECT JSON_ARRAYAGG(a [FORMAT] [RETURNING] [ON NULL]) FROM (query) q(a))
*/
static Node *
transformJsonArrayQueryConstructor(ParseState *pstate,
JsonArrayQueryConstructor *ctor)
{
SubLink *sublink = makeNode(SubLink);
SelectStmt *select = makeNode(SelectStmt);
RangeSubselect *range = makeNode(RangeSubselect);
Alias *alias = makeNode(Alias);
ResTarget *target = makeNode(ResTarget);
JsonArrayAgg *agg = makeNode(JsonArrayAgg);
ColumnRef *colref = makeNode(ColumnRef);
Query *query;
ParseState *qpstate;
/* Transform query only for counting target list entries. */
qpstate = make_parsestate(pstate);
query = transformStmt(qpstate, ctor->query);
if (count_nonjunk_tlist_entries(query->targetList) != 1)
ereport(ERROR,
errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return only one column"),
parser_errposition(pstate, ctor->location));
free_parsestate(qpstate);
colref->fields = list_make2(makeString(pstrdup("q")),
makeString(pstrdup("a")));
colref->location = ctor->location;
agg->arg = makeJsonValueExpr((Expr *) colref, ctor->format);
agg->absent_on_null = ctor->absent_on_null;
agg->constructor = makeNode(JsonAggConstructor);
agg->constructor->agg_order = NIL;
agg->constructor->output = ctor->output;
agg->constructor->location = ctor->location;
target->name = NULL;
target->indirection = NIL;
target->val = (Node *) agg;
target->location = ctor->location;
alias->aliasname = pstrdup("q");
alias->colnames = list_make1(makeString(pstrdup("a")));
range->lateral = false;
range->subquery = ctor->query;
range->alias = alias;
select->targetList = list_make1(target);
select->fromClause = list_make1(range);
sublink->subLinkType = EXPR_SUBLINK;
sublink->subLinkId = 0;
sublink->testexpr = NULL;
sublink->operName = NIL;
sublink->subselect = (Node *) select;
sublink->location = ctor->location;
return transformExprRecurse(pstate, (Node *) sublink);
}
/*
* Common code for JSON_OBJECTAGG and JSON_ARRAYAGG transformation.
*/
static Node *
transformJsonAggConstructor(ParseState *pstate, JsonAggConstructor *agg_ctor,
JsonReturning *returning, List *args,
Oid aggfnoid, Oid aggtype,
JsonConstructorType ctor_type,
bool unique, bool absent_on_null)
{
Node *node;
Expr *aggfilter;
aggfilter = agg_ctor->agg_filter ? (Expr *)
transformWhereClause(pstate, agg_ctor->agg_filter,
EXPR_KIND_FILTER, "FILTER") : NULL;
if (agg_ctor->over)
{
/* window function */
WindowFunc *wfunc = makeNode(WindowFunc);
wfunc->winfnoid = aggfnoid;
wfunc->wintype = aggtype;
/* wincollid and inputcollid will be set by parse_collate.c */
wfunc->args = args;
wfunc->aggfilter = aggfilter;
/* winref will be set by transformWindowFuncCall */
wfunc->winstar = false;
wfunc->winagg = true;
wfunc->location = agg_ctor->location;
/*
* ordered aggs not allowed in windows yet
*/
if (agg_ctor->agg_order != NIL)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("aggregate ORDER BY is not implemented for window functions"),
parser_errposition(pstate, agg_ctor->location));
/* parse_agg.c does additional window-func-specific processing */
transformWindowFuncCall(pstate, wfunc, agg_ctor->over);
node = (Node *) wfunc;
}
else
{
Aggref *aggref = makeNode(Aggref);
aggref->aggfnoid = aggfnoid;
aggref->aggtype = aggtype;
/* aggcollid and inputcollid will be set by parse_collate.c */
/* aggtranstype will be set by planner */
/* aggargtypes will be set by transformAggregateCall */
/* aggdirectargs and args will be set by transformAggregateCall */
/* aggorder and aggdistinct will be set by transformAggregateCall */
aggref->aggfilter = aggfilter;
aggref->aggstar = false;
aggref->aggvariadic = false;
aggref->aggkind = AGGKIND_NORMAL;
aggref->aggpresorted = false;
/* agglevelsup will be set by transformAggregateCall */
aggref->aggsplit = AGGSPLIT_SIMPLE; /* planner might change this */
aggref->aggno = -1; /* planner will set aggno and aggtransno */
aggref->aggtransno = -1;
aggref->location = agg_ctor->location;
transformAggregateCall(pstate, aggref, args, agg_ctor->agg_order, false);
node = (Node *) aggref;
}
return makeJsonConstructorExpr(pstate, ctor_type, NIL, (Expr *) node,
returning, unique, absent_on_null,
agg_ctor->location);
}
/*
* Transform JSON_OBJECTAGG() aggregate function.
*
* JSON_OBJECTAGG() is transformed into
* json[b]_objectagg[_unique][_strict](key, value) call depending on
* the output JSON format. Then the function call result is coerced to the
* target output type.
*/
static Node *
transformJsonObjectAgg(ParseState *pstate, JsonObjectAgg *agg)
{
JsonReturning *returning;
Node *key;
Node *val;
List *args;
Oid aggfnoid;
Oid aggtype;
key = transformExprRecurse(pstate, (Node *) agg->arg->key);
val = transformJsonValueExpr(pstate, agg->arg->value, JS_FORMAT_DEFAULT);
args = list_make2(key, val);
returning = transformJsonConstructorOutput(pstate, agg->constructor->output,
args);
if (returning->format->format_type == JS_FORMAT_JSONB)
{
if (agg->absent_on_null)
if (agg->unique)
aggfnoid = F_JSONB_OBJECT_AGG_UNIQUE_STRICT;
else
aggfnoid = F_JSONB_OBJECT_AGG_STRICT;
else if (agg->unique)
aggfnoid = F_JSONB_OBJECT_AGG_UNIQUE;
else
aggfnoid = F_JSONB_OBJECT_AGG;
aggtype = JSONBOID;
}
else
{
if (agg->absent_on_null)
if (agg->unique)
aggfnoid = F_JSON_OBJECT_AGG_UNIQUE_STRICT;
else
aggfnoid = F_JSON_OBJECT_AGG_STRICT;
else if (agg->unique)
aggfnoid = F_JSON_OBJECT_AGG_UNIQUE;
else
aggfnoid = F_JSON_OBJECT_AGG;
aggtype = JSONOID;
}
return transformJsonAggConstructor(pstate, agg->constructor, returning,
args, aggfnoid, aggtype,
JSCTOR_JSON_OBJECTAGG,
agg->unique, agg->absent_on_null);
}
/*
* Transform JSON_ARRAYAGG() aggregate function.
*
* JSON_ARRAYAGG() is transformed into json[b]_agg[_strict]() call depending
* on the output JSON format and absent_on_null. Then the function call result
* is coerced to the target output type.
*/
static Node *
transformJsonArrayAgg(ParseState *pstate, JsonArrayAgg *agg)
{
JsonReturning *returning;
Node *arg;
Oid aggfnoid;
Oid aggtype;
arg = transformJsonValueExpr(pstate, agg->arg, JS_FORMAT_DEFAULT);
returning = transformJsonConstructorOutput(pstate, agg->constructor->output,
list_make1(arg));
if (returning->format->format_type == JS_FORMAT_JSONB)
{
aggfnoid = agg->absent_on_null ? F_JSONB_AGG_STRICT : F_JSONB_AGG;
aggtype = JSONBOID;
}
else
{
aggfnoid = agg->absent_on_null ? F_JSON_AGG_STRICT : F_JSON_AGG;
aggtype = JSONOID;
}
return transformJsonAggConstructor(pstate, agg->constructor, returning,
list_make1(arg), aggfnoid, aggtype,
JSCTOR_JSON_ARRAYAGG,
false, agg->absent_on_null);
}
/*
* Transform JSON_ARRAY() constructor.
*
* JSON_ARRAY() is transformed into json[b]_build_array[_ext]() call
* depending on the output JSON format. The first argument of
* json[b]_build_array_ext() is absent_on_null.
*
* Then function call result is coerced to the target type.
*/
static Node *
transformJsonArrayConstructor(ParseState *pstate, JsonArrayConstructor *ctor)
{
JsonReturning *returning;
List *args = NIL;
/* transform element expressions, if any */
if (ctor->exprs)
{
ListCell *lc;
/* transform and append element arguments */
foreach(lc, ctor->exprs)
{
JsonValueExpr *jsval = castNode(JsonValueExpr, lfirst(lc));
Node *val = transformJsonValueExpr(pstate, jsval,
JS_FORMAT_DEFAULT);
args = lappend(args, val);
}
}
returning = transformJsonConstructorOutput(pstate, ctor->output, args);
return makeJsonConstructorExpr(pstate, JSCTOR_JSON_ARRAY, args, NULL,
returning, false, ctor->absent_on_null,
ctor->location);
}
static Node *
transformJsonParseArg(ParseState *pstate, Node *jsexpr, JsonFormat *format,
Oid *exprtype)
{
Node *raw_expr = transformExprRecurse(pstate, jsexpr);
Node *expr = raw_expr;
*exprtype = exprType(expr);
/* prepare input document */
if (*exprtype == BYTEAOID)
{
JsonValueExpr *jve;
expr = makeCaseTestExpr(raw_expr);
expr = makeJsonByteaToTextConversion(expr, format, exprLocation(expr));
*exprtype = TEXTOID;
jve = makeJsonValueExpr((Expr *) raw_expr, format);
jve->formatted_expr = (Expr *) expr;
expr = (Node *) jve;
}
else
{
char typcategory;
bool typispreferred;
get_type_category_preferred(*exprtype, &typcategory, &typispreferred);
if (*exprtype == UNKNOWNOID || typcategory == TYPCATEGORY_STRING)
{
expr = coerce_to_target_type(pstate, (Node *) expr, *exprtype,
TEXTOID, -1,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST, -1);
*exprtype = TEXTOID;
}
if (format->encoding != JS_ENC_DEFAULT)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
parser_errposition(pstate, format->location),
errmsg("cannot use JSON FORMAT ENCODING clause for non-bytea input types")));
}
return expr;
}
/*
* Transform IS JSON predicate.
*/
static Node *
transformJsonIsPredicate(ParseState *pstate, JsonIsPredicate *pred)
{
Oid exprtype;
Node *expr = transformJsonParseArg(pstate, pred->expr, pred->format,
&exprtype);
/* make resulting expression */
if (exprtype != TEXTOID && exprtype != JSONOID && exprtype != JSONBOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot use type %s in IS JSON predicate",
format_type_be(exprtype))));
/* This intentionally(?) drops the format clause. */
return makeJsonIsPredicate(expr, NULL, pred->item_type,
pred->unique_keys, pred->location);
}
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