diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 7cc1fdbd541774a49c9b2ec31f211fc990d09f44..e46e66eae80eabfb8ace3395259ec5820bae0645 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.117 2005/11/22 18:17:16 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.118 2006/01/10 21:59:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -161,7 +161,7 @@ scanNameSpaceForRelid(ParseState *pstate, Oid relid)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
- /* yes, the test for alias==NULL should be there... */
+ /* yes, the test for alias == NULL should be there... */
if (rte->rtekind == RTE_RELATION &&
rte->relid == relid &&
rte->alias == NULL)
@@ -177,6 +177,48 @@ scanNameSpaceForRelid(ParseState *pstate, Oid relid)
return result;
}
+/*
+ * searchRangeTable
+ * See if any RangeTblEntry could possibly match the RangeVar.
+ * If so, return a pointer to the RangeTblEntry; else return NULL.
+ *
+ * This is different from refnameRangeTblEntry in that it considers every
+ * entry in the ParseState's rangetable(s), not only those that are currently
+ * visible in the p_relnamespace lists. This behavior is invalid per the SQL
+ * spec, and it may give ambiguous results (there might be multiple equally
+ * valid matches, but only one will be returned). This must be used ONLY
+ * as a heuristic in giving suitable error messages. See warnAutoRange.
+ *
+ * Notice that we consider both matches on actual relation name and matches
+ * on alias.
+ */
+static RangeTblEntry *
+searchRangeTable(ParseState *pstate, RangeVar *relation)
+{
+ Oid relId = RangeVarGetRelid(relation, true);
+ char *refname = relation->relname;
+
+ while (pstate != NULL)
+ {
+ ListCell *l;
+
+ foreach(l, pstate->p_rtable)
+ {
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+
+ if (OidIsValid(relId) &&
+ rte->rtekind == RTE_RELATION &&
+ rte->relid == relId)
+ return rte;
+ if (strcmp(rte->eref->aliasname, refname) == 0)
+ return rte;
+ }
+
+ pstate = pstate->parentParseState;
+ }
+ return NULL;
+}
+
/*
* Check for relation-name conflicts between two relnamespace lists.
* Raise an error if any is found.
@@ -1005,6 +1047,8 @@ addImplicitRTE(ParseState *pstate, RangeVar *relation)
{
RangeTblEntry *rte;
+ /* issue warning or error as needed */
+ warnAutoRange(pstate, relation);
/*
* Note that we set inFromCl true, so that the RTE will be listed
* explicitly if the parsetree is ever decompiled by ruleutils.c. This
@@ -1014,7 +1058,6 @@ addImplicitRTE(ParseState *pstate, RangeVar *relation)
rte = addRangeTableEntry(pstate, relation, NULL, false, true);
/* Add to joinlist and relnamespace, but not varnamespace */
addRTEtoQuery(pstate, rte, true, true, false);
- warnAutoRange(pstate, relation);
return rte;
}
@@ -1761,31 +1804,68 @@ attnumTypeId(Relation rd, int attid)
static void
warnAutoRange(ParseState *pstate, RangeVar *relation)
{
+ RangeTblEntry *rte;
+ int sublevels_up;
+ const char *badAlias = NULL;
+
+ /*
+ * Check to see if there are any potential matches in the query's
+ * rangetable. This affects the message we provide.
+ */
+ rte = searchRangeTable(pstate, relation);
+
+ /*
+ * If we found a match that has an alias and the alias is visible in
+ * the namespace, then the problem is probably use of the relation's
+ * real name instead of its alias, ie "SELECT foo.* FROM foo f".
+ * This mistake is common enough to justify a specific hint.
+ *
+ * If we found a match that doesn't meet those criteria, assume the
+ * problem is illegal use of a relation outside its scope, as in the
+ * MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
+ */
+ if (rte && rte->alias &&
+ strcmp(rte->eref->aliasname, relation->relname) != 0 &&
+ refnameRangeTblEntry(pstate, NULL, rte->eref->aliasname,
+ &sublevels_up) == rte)
+ badAlias = rte->eref->aliasname;
+
if (!add_missing_from)
{
- if (pstate->parentParseState != NULL)
+ if (rte)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
- errmsg("missing FROM-clause entry in subquery for table \"%s\"",
- relation->relname)));
+ errmsg("invalid reference to FROM-clause entry for table \"%s\"",
+ relation->relname),
+ (badAlias ?
+ errhint("Perhaps you meant to reference the table alias \"%s\".",
+ badAlias) :
+ errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
+ rte->eref->aliasname))));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
- errmsg("missing FROM-clause entry for table \"%s\"",
- relation->relname)));
+ (pstate->parentParseState ?
+ errmsg("missing FROM-clause entry in subquery for table \"%s\"",
+ relation->relname) :
+ errmsg("missing FROM-clause entry for table \"%s\"",
+ relation->relname))));
}
else
{
/* just issue a warning */
- if (pstate->parentParseState != NULL)
- ereport(NOTICE,
- (errcode(ERRCODE_UNDEFINED_TABLE),
- errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
- relation->relname)));
- else
- ereport(NOTICE,
- (errcode(ERRCODE_UNDEFINED_TABLE),
+ ereport(NOTICE,
+ (errcode(ERRCODE_UNDEFINED_TABLE),
+ (pstate->parentParseState ?
+ errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
+ relation->relname) :
errmsg("adding missing FROM-clause entry for table \"%s\"",
- relation->relname)));
+ relation->relname)),
+ (badAlias ?
+ errhint("Perhaps you meant to reference the table alias \"%s\".",
+ badAlias) :
+ (rte ?
+ errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
+ rte->eref->aliasname) : 0))));
}
}
diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index f0b4791df45b7b83f937bd249b6ab85ed1f38818..fc46dd14e19007b6acf7d027eade73c80fc2b807 100644
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -60,7 +60,7 @@ select * from quadtable;
(2 rows)
select f1, q.c1 from quadtable; -- fails, q is a table reference
-ERROR: relation "q" does not exist
+ERROR: missing FROM-clause entry for table "q"
select f1, (q).c1, (qq.q).c1.i from quadtable qq;
f1 | c1 | i
----+-----------+-----