Files
oracle/tpt/demos/scalar_subquery_unnesting.sql
2026-03-12 21:23:47 +01:00

40 lines
874 B
SQL

-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
-- DROP TABLE test_users;
-- DROP TABLE test_objects;
CREATE TABLE test_users AS SELECT * FROM all_users;
CREATE TABLE test_objects AS SELECT * FROM all_objects;
@gts test_users
@gts test_objects
@53on
SELECT /*+ GATHER_PLAN_STATISTICS */
u.username
, (SELECT MAX(created) FROM test_objects o WHERE o.owner = u.username)
FROM
test_users u
WHERE
username LIKE 'S%'
/
@53off
@xall
@53on
-- ALTER SESSION SET "_optimizer_unnest_scalar_sq" = FALSE;
SELECT /*+ GATHER_PLAN_STATISTICS NO_UNNEST(@ssq) */
u.username
, (SELECT /*+ QB_NAME(ssq) */ MAX(created) FROM test_objects o WHERE o.owner = u.username)
FROM
test_users u
WHERE
username LIKE 'S%'
/
@53off
@xall