Generate a reasonable error message when an aggregate function is applied

to an undecorated relation name (cf. example from Ed Loehr, 5/25/00).

diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 3b543c3d6137dcf8d6badcd1040f673b79539888..ed6a910f273ee83f5b0d45c42c21443b1152df5c 100644 (file)
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.78 2000/04/12 17:15:26 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.79 2000/05/26 03:56:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -271,6 +271,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
    Node       *retval;
    bool        retset;
    bool        must_be_agg = agg_star || agg_distinct;
+   bool        could_be_agg;
    bool        attisset = false;
    Oid         toid = InvalidOid;
    Expr       *expr;
@@ -291,7 +292,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
    if (nargs == 1 && !must_be_agg)
    {
        /* Is it a plain Relation name from the parser? */
-       if (IsA(first_arg, Ident) &&((Ident *) first_arg)->isRel)
+       if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel)
        {
            Ident      *ident = (Ident *) first_arg;
            RangeTblEntry *rte;
@@ -413,28 +414,31 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
        }
    }
 
-   if (nargs == 1 || must_be_agg)
+   /*
+    * See if it's an aggregate.
+    */
+   if (must_be_agg)
    {
-
-       /*
-        * See if it's an aggregate.
-        */
-       Oid         basetype;
-       int         ncandidates;
-       CandidateList candidates;
-
        /* We don't presently cope with, eg, foo(DISTINCT x,y) */
        if (nargs != 1)
            elog(ERROR, "Aggregate functions may only have one parameter");
+       /* Agg's argument can't be a relation name, either */
+       if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel)
+           elog(ERROR, "Aggregate functions cannot be applied to relation names");
+       could_be_agg = true;
+   }
+   else
+   {
+       /* Try to parse as an aggregate if above-mentioned checks are OK */
+       could_be_agg = (nargs == 1) &&
+           !(IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel);
+   }
 
-       /*
-        * the aggregate COUNT is a special case, ignore its base type.
-        * Treat it as zero.   XXX mighty ugly --- FIXME
-        */
-       if (strcmp(funcname, "count") == 0)
-           basetype = 0;
-       else
-           basetype = exprType(lfirst(fargs));
+   if (could_be_agg)
+   {
+       Oid         basetype = exprType(lfirst(fargs));
+       int         ncandidates;
+       CandidateList candidates;
 
        /* try for exact match first... */
        if (SearchSysCacheTuple(AGGNAME,
@@ -445,9 +449,18 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
                                     fargs, agg_star, agg_distinct,
                                     precedence);
 
+       /* check for aggregate-that-accepts-any-type (eg, COUNT) */
+       if (SearchSysCacheTuple(AGGNAME,
+                               PointerGetDatum(funcname),
+                               ObjectIdGetDatum(0),
+                               0, 0))
+           return (Node *) ParseAgg(pstate, funcname, 0,
+                                    fargs, agg_star, agg_distinct,
+                                    precedence);
+
        /*
         * No exact match yet, so see if there is another entry in the
-        * aggregate table which is compatible. - thomas 1998-12-05
+        * aggregate table that is compatible. - thomas 1998-12-05
         */
        ncandidates = agg_get_candidates(funcname, basetype, &candidates);
        if (ncandidates > 0)
@@ -497,7 +510,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
    {
        Node       *arg = lfirst(i);
 
-       if (IsA(arg, Ident) &&((Ident *) arg)->isRel)
+       if (IsA(arg, Ident) && ((Ident *) arg)->isRel)
        {
            RangeTblEntry *rte;
            int         vnum;