题解 | 42#删除emp_no重复的记录，只保留最小的id对应的记录。#

错误代码

delete from titles_test
  where id not in (select min(id) from titles_test group by emp_no)

正确代码：

DELETE FROM titles_test
WHERE id NOT IN(
    SELECT * FROM(
    SELECT MIN(id)
    FROM titles_test
    GROUP BY emp_no)a);

思路：看了别人代码才知道，MySQL中不允许在子查询的同时删除表数据（不能一边查一边把查的表删了）