题解 | #删除emp_no重复的记录，只保留最小的id对应的记录。#

emp_no重复的记录

select emp_no
from titles_test
group by emp_no
having count(emp_no)>1

最小的id对应的记录

select min(id)
from titles_test
group by emp_no
having count(emp_no)>1

删除emp_no重复的记录，只保留最小的id对应的记录。

delete from titles_test
where emp_no in(
select emp_no
from titles_test
group by emp_no
having count(emp_no)>1)
and id not in (
select min(id)
from titles_test
group by emp_no
having count(emp_no)>1)