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| author | Dean Rasheed <dean.a.rasheed@gmail.com> | 2024-03-17 13:58:59 +0000 |
|---|---|---|
| committer | Dean Rasheed <dean.a.rasheed@gmail.com> | 2024-03-17 13:58:59 +0000 |
| commit | c649fa24a42ba89bf5460c7110e4fc8eeca65959 (patch) | |
| tree | de7d51489c6c6fff56fddad66c0ced2aa427d6a5 /src/backend/rewrite/rewriteHandler.c | |
| parent | 6a004f1be87d34cfe51acf2fe2552d2b08a79273 (diff) | |
| download | postgresql-c649fa24a42ba89bf5460c7110e4fc8eeca65959.tar.gz postgresql-c649fa24a42ba89bf5460c7110e4fc8eeca65959.zip | |
Add RETURNING support to MERGE.
This allows a RETURNING clause to be appended to a MERGE query, to
return values based on each row inserted, updated, or deleted. As with
plain INSERT, UPDATE, and DELETE commands, the returned values are
based on the new contents of the target table for INSERT and UPDATE
actions, and on its old contents for DELETE actions. Values from the
source relation may also be returned.
As with INSERT/UPDATE/DELETE, the output of MERGE ... RETURNING may be
used as the source relation for other operations such as WITH queries
and COPY commands.
Additionally, a special function merge_action() is provided, which
returns 'INSERT', 'UPDATE', or 'DELETE', depending on the action
executed for each row. The merge_action() function can be used
anywhere in the RETURNING list, including in arbitrary expressions and
subqueries, but it is an error to use it anywhere outside of a MERGE
query's RETURNING list.
Dean Rasheed, reviewed by Isaac Morland, Vik Fearing, Alvaro Herrera,
Gurjeet Singh, Jian He, Jeff Davis, Merlin Moncure, Peter Eisentraut,
and Wolfgang Walther.
Discussion: http://postgr.es/m/CAEZATCWePEGQR5LBn-vD6SfeLZafzEm2Qy_L_Oky2=qw2w3Pzg@mail.gmail.com
Diffstat (limited to 'src/backend/rewrite/rewriteHandler.c')
| -rw-r--r-- | src/backend/rewrite/rewriteHandler.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c index 7a46e8b3541..9fd05b15e73 100644 --- a/src/backend/rewrite/rewriteHandler.c +++ b/src/backend/rewrite/rewriteHandler.c @@ -3833,9 +3833,9 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length) ListCell *lc1; /* - * First, recursively process any insert/update/delete statements in WITH - * clauses. (We have to do this first because the WITH clauses may get - * copied into rule actions below.) + * First, recursively process any insert/update/delete/merge statements in + * WITH clauses. (We have to do this first because the WITH clauses may + * get copied into rule actions below.) */ foreach(lc1, parsetree->cteList) { @@ -3860,7 +3860,8 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length) if (!(ctequery->commandType == CMD_SELECT || ctequery->commandType == CMD_UPDATE || ctequery->commandType == CMD_INSERT || - ctequery->commandType == CMD_DELETE)) + ctequery->commandType == CMD_DELETE || + ctequery->commandType == CMD_MERGE)) { /* * Currently it could only be NOTIFY; this error message will |