期望得到的结果什么? 如果仅是随便的唯一,则可以使用 group by select a.*,b.title as btitle,b.time as btime,c.title as ctitle,c.time as ctime,d.title as dtitle,d.time as dtime
from a表 as a left join B表 as b on a. userid=b.userid
left join C表 as c on a.userid=c.userid
left join D表 as d on a.userid = d.userid
group by a.ID
from a表 as a left join B表 as b on a. userid=b.userid
left join C表 as c on a.userid=c.userid
left join D表 as d on a.userid = d.userid
group by a.ID
解决方案 »
免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货