Suppose there is such a data:
select * from user
If the query result is like this:
id -- openid -- nick 1 -- o1 -- aaa 2 -- o1 -- aaa1 3 -- o1 -- aaa2 4 -- o2 -- bbb select * from user group by openid
At this time, the record with id=1 was found.
What if I want to get the second record from group by? That is, take out the records of 2-O1-AAA 1
select * from user where openid in ( select openid from user group by openid) limit 1,1