diff options
Diffstat (limited to 'src/backend/parser/parse_relation.c')
| -rw-r--r-- | src/backend/parser/parse_relation.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c index 926dcbf30e2..4e635561aaf 100644 --- a/src/backend/parser/parse_relation.c +++ b/src/backend/parser/parse_relation.c @@ -1577,7 +1577,11 @@ addRangeTableEntryForRelation(ParseState *pstate, * Then, construct and return a ParseNamespaceItem for the new RTE. * * This is much like addRangeTableEntry() except that it makes a subquery RTE. - * Note that an alias clause *must* be supplied. + * + * If the subquery does not have an alias, the auto-generated relation name in + * the returned ParseNamespaceItem will be marked as not visible, and so only + * unqualified references to the subquery columns will be allowed, and the + * relation name will not conflict with others in the pstate's namespace list. */ ParseNamespaceItem * addRangeTableEntryForSubquery(ParseState *pstate, @@ -1587,7 +1591,6 @@ addRangeTableEntryForSubquery(ParseState *pstate, bool inFromCl) { RangeTblEntry *rte = makeNode(RangeTblEntry); - char *refname = alias->aliasname; Alias *eref; int numaliases; List *coltypes, @@ -1595,6 +1598,7 @@ addRangeTableEntryForSubquery(ParseState *pstate, *colcollations; int varattno; ListCell *tlistitem; + ParseNamespaceItem *nsitem; Assert(pstate != NULL); @@ -1602,7 +1606,7 @@ addRangeTableEntryForSubquery(ParseState *pstate, rte->subquery = subquery; rte->alias = alias; - eref = copyObject(alias); + eref = alias ? copyObject(alias) : makeAlias("unnamed_subquery", NIL); numaliases = list_length(eref->colnames); /* fill in any unspecified alias columns, and extract column type info */ @@ -1634,7 +1638,7 @@ addRangeTableEntryForSubquery(ParseState *pstate, ereport(ERROR, (errcode(ERRCODE_INVALID_COLUMN_REFERENCE), errmsg("table \"%s\" has %d columns available but %d columns specified", - refname, varattno, numaliases))); + eref->aliasname, varattno, numaliases))); rte->eref = eref; @@ -1665,8 +1669,15 @@ addRangeTableEntryForSubquery(ParseState *pstate, * Build a ParseNamespaceItem, but don't add it to the pstate's namespace * list --- caller must do that if appropriate. */ - return buildNSItemFromLists(rte, list_length(pstate->p_rtable), - coltypes, coltypmods, colcollations); + nsitem = buildNSItemFromLists(rte, list_length(pstate->p_rtable), + coltypes, coltypmods, colcollations); + + /* + * Mark it visible as a relation name only if it had a user-written alias. + */ + nsitem->p_rel_visible = (alias != NULL); + + return nsitem; } /* @@ -2520,6 +2531,10 @@ addRangeTableEntryForENR(ParseState *pstate, * This is used when we have not yet done transformLockingClause, but need * to know the correct lock to take during initial opening of relations. * + * Note that refname may be NULL (for a subquery without an alias), in which + * case the relation can't be locked by name, but it might still be locked if + * a locking clause requests that all tables be locked. + * * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE, * since the table-level lock is the same either way. */ @@ -2544,7 +2559,7 @@ isLockedRefname(ParseState *pstate, const char *refname) /* all tables used in query */ return true; } - else + else if (refname != NULL) { /* just the named tables */ ListCell *l2; |