database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-08-28 18:48:04 +03:00
Code Activity

Add RETURNING support to MERGE.

Browse Source 
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
This commit is contained in:
Dean Rasheed
2024-03-17 13:58:59 +00:00
parent 6a004f1be8
commit c649fa24a4
61 changed files with 1198 additions and 216 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
doc/src/sgml/queries.sgml
View File

@@ -2063,9 +2063,10 @@ SELECT <replaceable>select_list</replaceable> FROM <replaceable>table_expression
Table Expressions or <acronym>CTE</acronym>s, can be thought of as defining
temporary tables that exist just for one query. Each auxiliary statement
in a <literal>WITH</literal> clause can be a <command>SELECT</command>,
<command>INSERT</command>, <command>UPDATE</command>, or <command>DELETE</command>; and the
<command>INSERT</command>, <command>UPDATE</command>, <command>DELETE</command>,
or <command>MERGE</command>; and the
<literal>WITH</literal> clause itself is attached to a primary statement that can
be a <command>SELECT</command>, <command>INSERT</command>, <command>UPDATE</command>,
also be a <command>SELECT</command>, <command>INSERT</command>, <command>UPDATE</command>,
<command>DELETE</command>, or <command>MERGE</command>.
</para>
@@ -2599,8 +2600,8 @@ SELECT * FROM w AS w1 JOIN w AS w2 ON w1.f = w2.f;
<title>Data-Modifying Statements in <literal>WITH</literal></title>
<para>
You can use most data-modifying statements (<command>INSERT</command>,
<command>UPDATE</command>, or <command>DELETE</command>, but not
You can use data-modifying statements (<command>INSERT</command>,
<command>UPDATE</command>, <command>DELETE</command>, or
<command>MERGE</command>) in <literal>WITH</literal>. This
allows you to perform several different operations in the same query.
An example is: