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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/executor/functions.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/executor/functions.c')
| -rw-r--r-- | src/backend/executor/functions.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c index 6e926ef4eed..539cd0a9991 100644 --- a/src/backend/executor/functions.c +++ b/src/backend/executor/functions.c @@ -1662,8 +1662,8 @@ check_sql_fn_retval(List *queryTreeLists, /* * If it's a plain SELECT, it returns whatever the targetlist says. - * Otherwise, if it's INSERT/UPDATE/DELETE with RETURNING, it returns - * that. Otherwise, the function return type must be VOID. + * Otherwise, if it's INSERT/UPDATE/DELETE/MERGE with RETURNING, it + * returns that. Otherwise, the function return type must be VOID. * * Note: eventually replace this test with QueryReturnsTuples? We'd need * a more general method of determining the output type, though. Also, it @@ -1681,7 +1681,8 @@ check_sql_fn_retval(List *queryTreeLists, else if (parse && (parse->commandType == CMD_INSERT || parse->commandType == CMD_UPDATE || - parse->commandType == CMD_DELETE) && + parse->commandType == CMD_DELETE || + parse->commandType == CMD_MERGE) && parse->returningList) { tlist = parse->returningList; @@ -1695,7 +1696,7 @@ check_sql_fn_retval(List *queryTreeLists, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), - errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING."))); + errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE/MERGE RETURNING."))); return false; /* keep compiler quiet */ } |