MySQL进行子查询（嵌套查询）时报错：Subquery returns more than 1 row

Subquery returns more than 1 row

子查询返回了多行数据

原因：子查询的时候返回了多条数据

报错代码：

SELECT * FROM emp WHERE deptno = (SELECT deptno FROM dept WHERE loc = '苏州');

解决方案一：使用ANY

SELECT * FROM emp WHERE deptno = ANY(SELECT deptno FROM dept WHERE loc = '苏州');

解决方案二：使用IN

SELECT * FROM emp WHERE deptno IN(SELECT deptno FROM dept WHERE loc = '苏州');