From 331c3c218b369d2f919c800654e4ca6e5f209aac Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 5 Aug 2010 21:45:45 +0000
Subject: [PATCH] Add a very specific hint for the case that we're unable to
locate a function matching a call like f(x, ORDER BY y,z). It could be that
what the user really wants is f(x,z ORDER BY y). We now have pretty
conclusive evidence that many people won't understand this problem without
concrete guidance, so give it to them. Per further discussion of the
string_agg() problem.
---
src/backend/parser/parse_func.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 7bc865e398..6ee9edcc2b 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.224.2.1 2010/07/29 23:16:41 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.224.2.2 2010/08/05 21:45:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -284,6 +284,19 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
errhint("Could not choose a best candidate function. "
"You might need to add explicit type casts."),
parser_errposition(pstate, location)));
+ else if (list_length(agg_order) > 1)
+ {
+ /* It's agg(x, ORDER BY y,z) ... perhaps misplaced ORDER BY */
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_FUNCTION),
+ errmsg("function %s does not exist",
+ func_signature_string(funcname, nargs, argnames,
+ actual_arg_types)),
+ errhint("No aggregate function matches the given name and argument types. "
+ "Perhaps you misplaced ORDER BY; ORDER BY must appear "
+ "after all regular arguments of the aggregate."),
+ parser_errposition(pstate, location)));
+ }
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
--
2.49.0