Question

如何在SQL Server中使用多个列和表选择不同的值？

这是我的代码：

SELECT registryno,registrystatus,psPatRegisters.pattrantype,PK_psPatRegisters,
       payername,*
FROM psPatRegisters,psPatinv
WHERE psPatRegisters.PK_psPatRegisters=psPatinv.FK_psPatRegisters
    AND registryno between '7133' and '7169'
    AND psPatinv.pattrantype='I'
GROUP BY psPatRegisters.PK_psPatRegisters

我的代码出了什么问题？

Answer 1

删除“group by”和“*”并使用distinct。或者您必须按所有选定的字段进行分组（不使用*），此时不需要使用

Answer 2

这会对你有用吗？

select distinct egistryno,registrystatus,
       psPatRegisters.pattrantype,PK_psPatRegisters,payername
from psPatRegisters,psPatinv
where psPatRegisters.PK_psPatRegisters=psPatinv.FK_psPatRegisters
and registryno between '7133' and '7169'
and psPatinv.pattrantype='I'

此外，如果没有聚合函数，则无法对不在分组子句中的列进行分组和选择。

Answer 3

投影中的所有列大多数都在分组依据中。

SELECT  registryno ,
    registrystatus ,
    psPatRegisters.pattrantype ,
    PK_psPatRegisters ,
    payername
FROM    psPatRegisters ,
    psPatinv
WHERE   psPatRegisters.PK_psPatRegisters = psPatinv.FK_psPatRegisters
    AND registryno BETWEEN '7133' AND '7169'
    AND psPatinv.pattrantype = 'I'
GROUP BY registryno ,
    registrystatus ,
    psPatRegisters.pattrantype ,
    PK_psPatRegisters ,
    payername

或使用DISTINCT KeyWord

SELECT  
DISTINCT
    registryno ,
    registrystatus ,
    psPatRegisters.pattrantype ,
    PK_psPatRegisters ,
    payername
FROM    psPatRegisters ,
    psPatinv
WHERE   psPatRegisters.PK_psPatRegisters = psPatinv.FK_psPatRegisters
    AND registryno BETWEEN '7133' AND '7169'
    AND psPatinv.pattrantype = 'I'

我认为如果您只想从结果中删除重复值，最好的方法是使用DISTINCT 但如果你想使用聚合函数（如Sum / Min / ...），你最常使用Group By

如何在SQL Server中使用多个列和表选择不同的值？

3 个答案: