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Allow FOR UPDATE to appear after LIMIT/OFFSET to match MySQL syntax and as 

a more logical ordering.
This commit is contained in:
Bruce Momjian 2002-08-28 14:35:37 +00:00
parent 8e4357d8ad
commit 6077db92c2
4 changed files with 43 additions and 32 deletions
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32
doc/src/sgml/ref/select.sgml
View File

@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.56 2002/08/15 02:59:18 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.57 2002/08/28 14:35:37 momjian Exp $
PostgreSQL documentation
-->
@ -28,9 +28,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
[ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
where <replaceable class="PARAMETER">from_item</replaceable> can be:
@ -107,9 +107,9 @@ where <replaceable class="PARAMETER">from_item</replaceable> can be:
<term><replaceable class="PARAMETER">select</replaceable></term>
<listitem>
<para>
A select statement with all features except the ORDER BY, FOR UPDATE,
and LIMIT clauses (even those can be used when the select is
parenthesized).
A select statement with all features except the ORDER BY,
LIMIT/OFFSET, and FOR UPDATE clauses (even those can be used when the
select is parenthesized).
</para>
</listitem>
</varlistentry>
@ -354,17 +354,17 @@ where <replaceable class="PARAMETER">from_item</replaceable> can be:
(See <xref linkend="sql-except" endterm="sql-except-title">.)
</para>
<para>
The FOR UPDATE clause allows the SELECT statement to perform
exclusive locking of selected rows.
</para>
<para>
The LIMIT clause allows a subset of the rows produced by the query
to be returned to the user.
(See <xref linkend="sql-limit" endterm="sql-limit-title">.)
</para>
<para>
The FOR UPDATE clause allows the SELECT statement to perform
exclusive locking of selected rows.
</para>
<para>
You must have SELECT privilege to a table to read its values
(See the <command>GRANT</command>/<command>REVOKE</command> statements).
@ -666,8 +666,8 @@ SELECT name FROM distributors ORDER BY code;
where
<replaceable class="PARAMETER">table_query</replaceable>
specifies any select expression without an ORDER BY, FOR UPDATE,
or LIMIT clause. (ORDER BY and LIMIT can be attached to a sub-expression
specifies any select expression without an ORDER BY, LIMIT, or FOR UPDATE
clause. (ORDER BY and LIMIT can be attached to a sub-expression
if it is enclosed in parentheses. Without parentheses, these clauses
will be taken to apply to the result of the UNION, not to its right-hand
input expression.)
@ -716,8 +716,8 @@ SELECT name FROM distributors ORDER BY code;
where
<replaceable class="PARAMETER">table_query</replaceable>
specifies any select expression without an ORDER BY, FOR UPDATE,
or LIMIT clause.
specifies any select expression without an ORDER BY, LIMIT, or
FOR UPDATE clause.
</para>
<para>
@ -757,8 +757,8 @@ SELECT name FROM distributors ORDER BY code;
where
<replaceable class="PARAMETER">table_query</replaceable>
specifies any select expression without an ORDER BY, FOR UPDATE,
or LIMIT clause.
specifies any select expression without an ORDER BY, LIMIT,
or FOR UPDATE clause.
</para>
<para>

4
doc/src/sgml/ref/select_into.sgml
View File

@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select_into.sgml,v 1.18 2002/04/23 02:07:16 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select_into.sgml,v 1.19 2002/08/28 14:35:37 momjian Exp $
PostgreSQL documentation
-->
@ -29,9 +29,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
[ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
where <replaceable class="PARAMETER">from_item</replaceable> can be:

4
doc/src/sgml/sql.sgml
View File

@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.26 2002/03/15 16:16:31 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.27 2002/08/28 14:35:36 momjian Exp $
-->
<chapter id="sql">
@ -863,9 +863,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">class_name</replaceable> [, ...] ] ]
[ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">class_name</replaceable> [, ...] ] ]
</synopsis>
</para>

35
src/backend/parser/gram.y
View File

@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.361 2002/08/27 04:55:08 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.362 2002/08/28 14:35:37 momjian Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -208,8 +208,8 @@ static void doNegateFloat(Value *v);
func_args_list, func_as, createfunc_opt_list
oper_argtypes, RuleActionList, RuleActionMulti,
opt_column_list, columnList, opt_name_list,
sort_clause, sortby_list, index_params, index_list,
name_list, from_clause, from_list, opt_array_bounds,
sort_clause, opt_sort_clause, sortby_list, index_params,
index_list,name_list, from_clause, from_list, opt_array_bounds,
qualified_name_list, any_name, any_name_list,
any_operator, expr_list, dotted_name, attrs,
target_list, update_target_list, insert_column_list,
@ -4180,26 +4180,32 @@ select_with_parens:
| '(' select_with_parens ')' { $$ = $2; }
;
/*
* FOR UPDATE may be before or after LIMIT/OFFSET.
* In <=7.2.X, LIMIT/OFFSET had to be after FOR UPDATE
* We now support both orderings, but prefer LIMIT/OFFSET before FOR UPDATE
* 2002-08-28 bjm
*/
select_no_parens:
simple_select { $$ = $1; }
| select_clause sort_clause opt_for_update_clause opt_select_limit
| select_clause sort_clause
{
insertSelectOptions((SelectStmt *) $1, $2, NIL,
NULL, NULL);
$$ = $1;
}
| select_clause opt_sort_clause for_update_clause opt_select_limit
{
insertSelectOptions((SelectStmt *) $1, $2, $3,
nth(0, $4), nth(1, $4));
$$ = $1;
}
| select_clause for_update_clause opt_select_limit
| select_clause opt_sort_clause select_limit opt_for_update_clause
{
insertSelectOptions((SelectStmt *) $1, NIL, $2,
insertSelectOptions((SelectStmt *) $1, $2, $4,
nth(0, $3), nth(1, $3));
$$ = $1;
}
| select_clause select_limit
{
insertSelectOptions((SelectStmt *) $1, NIL, NIL,
nth(0, $2), nth(1, $2));
$$ = $1;
}
;
select_clause:
@ -4335,6 +4341,11 @@ opt_distinct:
| /*EMPTY*/ { $$ = NIL; }
;
opt_sort_clause:
sort_clause { $$ = $1;}
| /*EMPTY*/ { $$ = NIL; }
;
sort_clause:
ORDER BY sortby_list { $$ = $3; }
;