Sql select 联合相同 table

Question

此致

我有以下表格

客户端

id, name, saler1, saler2, saler3, dateSale...

人员

id, name...

我的查询是

select S1.*, S2.* 
from Client C 
left join Personnel S1.id on = C.saler1
left Join Personnel S2.id on = C.saler2

我的结果是

S1.id, S1.name ... S2.id, S2.name

但我只想要一列，例如 Personnel

|id | name |
|sa1| name |
|sa2| name |

有人可以帮助我吗？

Answer 1

我猜你正在寻找 Union All

select S1.* From Client C Left join Personnel S1.id on = C.saler1
UNION ALL
select S1.* From Client C Left join Personnel S1.id on = C.saler2

Answer 2

不完全确定你在问什么，但从你已经写的查询来看，我认为你正在寻找这样的东西......

Select *
FROM (
SELECT id, name, saler1 AS Saler, dateSale FROM Client Where saler1 IS NOT NULL
UNION ALL 
SELECT id, name, saler2 AS Saler, dateSale FROM Client Where saler2 IS NOT NULL
UNION ALL 
SELECT id, name, saler3 AS Saler, dateSale FROM Client Where saler3 IS NOT NULL
) C
Left join Personnel P  on P.id  = C.saler

因为这就是您想要的，另一种巧妙的方法是使用 UNPIVOT 之类的东西，例如 ....

Select P.* , up.id, up.dated
FROM Client UNPIVOT (
                      Salers for Saler IN (Saler1,Saler2,Saler3)
                     )up
LEFT JOIN Personnel P ON up.Salers = P.id

Sql select 联合相同 table

Sql select union same table

sql-server

union

join