DROP TABLE IF EXISTS t1; CREATE TABLE t1 (a , b , (b)) ENGINE= ; INSERT INTO t1 (a,b) VALUES (1,'a'),(2,'b'),(3,'c'),(4,'d'),(5,'e'),(6,'x'),(7,'y'),(8,'z'); DELETE FROM t1 WHERE b > 'y'; DELETE FROM t1 WHERE a=2; SELECT a,b FROM t1; a b 1 a 3 c 4 d 5 e 6 x 7 y DELETE FROM t1; DROP TABLE t1; CREATE TABLE t1 (a PRIMARY KEY, b ) ENGINE= ; INSERT INTO t1 (a,b) VALUES (1,'a'),(2,'b'),(3,'c'),(4,'d'),(5,'e'),(6,'x'),(7,'y'),(8,'z'); DELETE FROM t1 WHERE b > 'y'; DELETE FROM t1 WHERE a=2; SELECT a,b FROM t1; a b 1 a 3 c 4 d 5 e 6 x 7 y DELETE FROM t1; DROP TABLE t1; CREATE TABLE t1 (a , b , c , (a), (b)) ENGINE= ; INSERT INTO t1 (a,b,c) VALUES (1,2,3),(4,5,6),(7,8,9); DELETE FROM t1 WHERE a = 10 OR b = 20 ORDER BY c LIMIT 1; SELECT a,b,c FROM t1; a b c 1 2 3 4 5 6 7 8 9 DROP TABLE t1;