MySQL 一对多查询，合并多的一方的信息

select   c.name,  (select   group_concat(name) from student   s   where  s.class_id =c.id ) from  class  c

select
    id,name,phone,
    sum(case when type='in' then 1 else 0 end) cnt_in,
    sum(case when type='out' then 1 else 0 end) cnt_out,
    sum(case when iflocal='1' then 1 else 0 end) cnt_local,
    sum(case when iflocal='0' then 1 else 0 end) cnt_nonlocal,
    sum(case when type='in' then input_time else 0 end) alltime_in,
    sum(case when type='out' then input_time else 0 end) alltime_out
from userlist a join phonelist b
on a.phone=b.phone group by a.phone;
来自：
http://blog.csdn.net/textalign/article/details/71746973