diff options
Diffstat (limited to 'src/backend/parser/parse_relation.c')
| -rw-r--r-- | src/backend/parser/parse_relation.c | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c index 491cbc5ef08..baae0a578cf 100644 --- a/src/backend/parser/parse_relation.c +++ b/src/backend/parser/parse_relation.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.47 2000/09/12 21:07:02 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.48 2000/09/25 18:14:54 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -713,6 +713,43 @@ expandNamesVars(ParseState *pstate, List *names, List *vars) return te_list; } +/* ---------- + * get_rte_attribute_name + * Get an attribute name from a RangeTblEntry + * + * This is unlike get_attname() because we use aliases if available. + * In particular, it will work on an RTE for a subselect, whereas + * get_attname() only works on real relations. + * ---------- + */ +char * +get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum) +{ + char *attname; + + /* + * If there is an alias, use it + */ + if (attnum > 0 && attnum <= length(rte->eref->attrs)) + return strVal(nth(attnum-1, rte->eref->attrs)); + /* + * Can get here for a system attribute (which never has an alias), + * or if alias name list is too short (which probably can't happen + * anymore). Neither of these cases is valid for a subselect RTE. + */ + if (rte->relid == InvalidOid) + elog(ERROR, "Invalid attnum %d for rangetable entry %s", + attnum, rte->eref->relname); + /* + * Use the real name of the table's column + */ + attname = get_attname(rte->relid, attnum); + if (attname == NULL) + elog(ERROR, "cache lookup of attribute %d in relation %u failed", + attnum, rte->relid); + return attname; +} + /* * given relation and att name, return id of variable * |