delete from titles_test where id not in( select*from (select min(id) from titles_test group by emp_no) n); SQL237:delete from titles_test where id not in(selectfrom (select min(id) from titles_test group by emp_no) n);在mysql中不支持delete删除子查询的实现,因此需要嵌套一层子查询selectfrom() t;同时可以通过 查询最小的加上group by获取多组中最小的数...