diff options
| author | Peter Eisentraut <peter@eisentraut.org> | 2021-02-01 13:54:59 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2021-02-01 14:32:51 +0100 |
| commit | 3696a600e2292d43c00949ddf0352e4ebb487e5b (patch) | |
| tree | 11f19c8c9e5757c44b8da02d0e1f7b41f8ec5f13 /src/backend/parser/parse_target.c | |
| parent | bb513b364b4fe31574574c8d0afbb2255268b321 (diff) | |
| download | postgresql-3696a600e2292d43c00949ddf0352e4ebb487e5b.tar.gz postgresql-3696a600e2292d43c00949ddf0352e4ebb487e5b.zip | |
SEARCH and CYCLE clauses
This adds the SQL standard feature that adds the SEARCH and CYCLE
clauses to recursive queries to be able to do produce breadth- or
depth-first search orders and detect cycles. These clauses can be
rewritten into queries using existing syntax, and that is what this
patch does in the rewriter.
Reviewed-by: Vik Fearing <vik@postgresfriends.org>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/db80ceee-6f97-9b4a-8ee8-3ba0c58e5be2@2ndquadrant.com
Diffstat (limited to 'src/backend/parser/parse_target.c')
| -rw-r--r-- | src/backend/parser/parse_target.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c index 7eaa076771a..51ecc16c42e 100644 --- a/src/backend/parser/parse_target.c +++ b/src/backend/parser/parse_target.c @@ -399,8 +399,23 @@ markTargetListOrigin(ParseState *pstate, TargetEntry *tle, { CommonTableExpr *cte = GetCTEForRTE(pstate, rte, netlevelsup); TargetEntry *ste; + List *tl = GetCTETargetList(cte); + int extra_cols = 0; + + /* + * RTE for CTE will already have the search and cycle columns + * added, but the subquery won't, so skip looking those up. + */ + if (cte->search_clause) + extra_cols += 1; + if (cte->cycle_clause) + extra_cols += 2; + if (extra_cols && + attnum > list_length(tl) && + attnum <= list_length(tl) + extra_cols) + break; - ste = get_tle_by_resno(GetCTETargetList(cte), attnum); + ste = get_tle_by_resno(tl, attnum); if (ste == NULL || ste->resjunk) elog(ERROR, "CTE %s does not have attribute %d", rte->eref->aliasname, attnum); |