1CREATE TABLE t1 ( a INT, b CHAR(3) ); 2INSERT INTO t1 VALUES ( 1, 'foo' ); 3CREATE TABLE t2 ( c CHAR(3), d INT ); 4INSERT INTO t2 VALUES ( 'foo', 1 ); 5UPDATE IGNORE t1, t2 SET b = 'bar', c = 'bar' 6 WHERE a != ( SELECT 1 UNION SELECT 2 ); 7Warnings: 8Warning 1242 Subquery returns more than 1 row 9DROP TABLE t1, t2; 10