Question

我有两个表Client和PIPOOrder。

它应显示alpha和beta（以及所有用户）匹配的最小和最大匹配项的所有条目

Client  | Order
alpha   |alpha  01/01/2004
beta    |alpha  02/02/2004
alpha1  |alpha  05/05/2014
Test    |beta   05/05/2014
test1   |beta   01/05/2014


select min(created_at) as FirstOrder,max(created_at) as LatestOrder from pipo_orders

这是我到目前为止所尝试的，我正在做的错误是什么，我该怎么做？

更新：

我需要在左连接

中执行此操作

Answer 1

select c.clientname,
       min(created_at) as FirstOrder,
       max(created_at) as LatestOrder 
from client c
left join pipo_orders p on c.clientid = p.clientid
group by c.clientid, c.clientname

SQLFiddle demo

Answer 2

像这样使用GROUP BY：

select Client, min(created_at) as FirstOrder,max(created_at) as LatestOrder from pipo_orders group by Client

Answer 3

感谢您的提问，我看着你Sql Fiddle。希望下面是你要找的：

select ClientName,pipo1.FirstOrder,pipo2.LastOrder
from client as c1 inner join
    (select ClientID,min(created_at) as FirstOrder from pipo_orders group by ClientID) 
    as pipo1 on c1.ClientID = pipo1.ClientID inner join 
    (select ClientID,max(created_at) as LastOrder from pipo_orders group by ClientID)
    as pipo2 on c1.ClientID = pipo2.ClientID

从两个表中选择所有匹配的最小值，最大值

更新：

3 个答案:

SQLFiddle demo