Control the execution order of UNION, EXCEPT, and INTERSECT operations. Learn how to use parentheses to define explicit operation priority.
You can control the ordering of execution on table operations using parentheses.
( expression )
[ORDER BY [column[, column...]]]
[LIMIT {[offset,] row_count | row_count OFFSET offset}]Using parentheses in SQL allows to control the order of execution for statements and , including , , and operations. MariaDB executes the parenthetical expression before the rest of the statement. You can then use and clauses the further organize the result set.
This page is licensed: CC BY-SA / Gnu FDL
CREATE TABLE test.t1 (num INT);
INSERT INTO test.t1 VALUES (1),(2),(3);
(SELECT * FROM test.t1
UNION
VALUES (10))
INTERSECT
VALUES (1),(3),(10),(11);
+------+
| num |
+------+
| 1 |
| 3 |
| 10 |
+------+
((SELECT * FROM test.t1
UNION
VALUES (10))
INTERSECT
VALUES (1),(3),(10),(11))
ORDER BY 1 DESC;
+------+
| num |
+------+
| 10 |
| 3 |
| 1 |
+------+