From fba999cb2c8aeafc113b965682bcc9f9ce081c88 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 18 Jul 2010 19:37:49 +0000 Subject: [PATCH] Allow ORDER BY/GROUP BY/etc items to match targetlist items regardless of any implicit casting previously applied to the targetlist item. This is reasonable because the implicit cast, by definition, wasn't written by the user; so we are preserving the expected behavior that ORDER BY items match textually equivalent tlist items. The case never arose before because there couldn't be any implicit casting of a top-level SELECT item before we process ORDER BY etc. But now it can arise in the context of aggregates containing ORDER BY clauses, since the "targetlist" is the already-casted list of arguments for the aggregate. The net effect is that the datatype used for ORDER BY/DISTINCT purposes is the aggregate's declared input type, not that of the original input column; which is a bit debatable but not horrendous, and to do otherwise would require major rework that doesn't seem justified. Per bug #5564 from Daniel Grace. Back-patch to 9.0 where aggregate ORDER BY was implemented. --- src/backend/parser/parse_clause.c | 17 +++++++++++++++-- src/test/regress/expected/aggregates.out | 21 +++++++++++++++++++++ src/test/regress/sql/aggregates.sql | 6 ++++++ 3 files changed, 42 insertions(+), 2 deletions(-) diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 182181f3a6..2c66a4ead5 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.198 2010/02/26 02:00:50 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.199 2010/07/18 19:37:48 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -21,6 +21,7 @@ #include "commands/defrem.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" +#include "optimizer/clauses.h" #include "optimizer/tlist.h" #include "optimizer/var.h" #include "parser/analyze.h" @@ -1430,8 +1431,20 @@ findTargetlistEntrySQL99(ParseState *pstate, Node *node, List **tlist) foreach(tl, *tlist) { TargetEntry *tle = (TargetEntry *) lfirst(tl); + Node *texpr; - if (equal(expr, tle->expr)) + /* + * Ignore any implicit cast on the existing tlist expression. + * + * This essentially allows the ORDER/GROUP/etc item to adopt the same + * datatype previously selected for a textually-equivalent tlist item. + * There can't be any implicit cast at top level in an ordinary SELECT + * tlist at this stage, but the case does arise with ORDER BY in an + * aggregate function. + */ + texpr = strip_implicit_coercions((Node *) tle->expr); + + if (equal(expr, texpr)) return tle; } diff --git a/src/test/regress/expected/aggregates.out b/src/test/regress/expected/aggregates.out index 2460d9dfd6..087b4679d4 100644 --- a/src/test/regress/expected/aggregates.out +++ b/src/test/regress/expected/aggregates.out @@ -830,3 +830,24 @@ select string_agg(a,',') from (values(null),(null)) g(a); (1 row) +-- check some implicit casting cases, as per bug #5564 +select string_agg(distinct f1 order by f1) from varchar_tbl; -- ok + string_agg +------------ + aababcd +(1 row) + +select string_agg(distinct f1::text order by f1) from varchar_tbl; -- not ok +ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list +LINE 1: select string_agg(distinct f1::text order by f1) from varcha... + ^ +select string_agg(distinct f1 order by f1::text) from varchar_tbl; -- not ok +ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list +LINE 1: select string_agg(distinct f1 order by f1::text) from varcha... + ^ +select string_agg(distinct f1::text order by f1::text) from varchar_tbl; -- ok + string_agg +------------ + aababcd +(1 row) + diff --git a/src/test/regress/sql/aggregates.sql b/src/test/regress/sql/aggregates.sql index daa89167a2..b2199d1ce9 100644 --- a/src/test/regress/sql/aggregates.sql +++ b/src/test/regress/sql/aggregates.sql @@ -362,3 +362,9 @@ select string_agg(a,',') from (values('aaaa'),('bbbb'),('cccc')) g(a); select string_agg(a,',') from (values('aaaa'),(null),('bbbb'),('cccc')) g(a); select string_agg(a,',') from (values(null),(null),('bbbb'),('cccc')) g(a); select string_agg(a,',') from (values(null),(null)) g(a); + +-- check some implicit casting cases, as per bug #5564 +select string_agg(distinct f1 order by f1) from varchar_tbl; -- ok +select string_agg(distinct f1::text order by f1) from varchar_tbl; -- not ok +select string_agg(distinct f1 order by f1::text) from varchar_tbl; -- not ok +select string_agg(distinct f1::text order by f1::text) from varchar_tbl; -- ok