MySQL進行子查詢（嵌套查詢）時報錯：Subquery returns more than 1 row

Subquery returns more than 1 row

子查詢返回了多行數據

原因：子查詢的時候返回了多條數據

報錯代碼：

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

解決方案一：使用ANY

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

解決方案二：使用IN

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