mysql基础

MySQL基础

企业面试题1

代码

select m.id,m.num 
from 
(
select t.id as id,count(1) num
from
(
select ra.requester_id as id
from RequestAccepted ra

union all
select ra.accepter_id as id
from RequestAccepted ra 
) t
group by t.id
) m
group by id
order by num desc,id 
limit 1

结果

总结

select from union union all where group by having order by limit