不建议使用子查询，能用链接的用链接，子查询影响服务器性能。
SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2);
DELETE FROM t1 WHERE s11 > ANY (SELECT COUNT(*) /* no hint */ FROM t2 WHERE NOT EXISTS (SELECT * FROM t3 WHERE ROW(5*t2.s1,77)= (SELECT 50,11*s1 FROM t4 UNION SELECT 50,77 FROM (SELECT * FROM t5) AS t5)));