Sql 基于另一列数据的列中的SUM（）数据

我有一个sql表

Project ID       Employee ID          Total Days

1                   100                   1
1                  100                   1
1                  100                   2
1                   100                   6
1                   200                   8
1                   200                   2

现在我需要这张桌子看起来像

Project ID       Employee ID          Total Days

1                   100                   10
1                   200                   10

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由于我是sql新手，基于上述条件使用SUM（）有点困惑。

下面的查询生成两列：

EmployeeID

，

totalDays

SELECT  EmployeeID, SUM(totalDays) totalDays
FROM    tableName
GROUP BY EmployeeID

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后续问题：为什么在您想要的结果中，

projectId

是

1和
？
这里有两种方法

Declare @t Table(ProjectId Int, EmployeeId Int,TotalDays Int)
Insert Into @t Values(1,100,1),(1,100,1),(1,100,2),(1,100,6),(1,200,8),(1,200,2)

方法1:

Select ProjectId,EmployeeId,TotalDays = Sum(TotalDays)
From @t 
Group By ProjectId,EmployeeId

;With Cte As(
Select 
    ProjectId
    ,EmployeeId
    ,TotalDays = Sum(TotalDays) Over(Partition By EmployeeId)
    ,Rn = Row_Number() Over(Partition By EmployeeId Order By EmployeeId)
From @t )
Select ProjectId,EmployeeId,TotalDays
From Cte Where Rn = 1

方法2:

Select ProjectId,EmployeeId,TotalDays = Sum(TotalDays)
From @t 
Group By ProjectId,EmployeeId

;With Cte As(
Select 
    ProjectId
    ,EmployeeId
    ,TotalDays = Sum(TotalDays) Over(Partition By EmployeeId)
    ,Rn = Row_Number() Over(Partition By EmployeeId Order By EmployeeId)
From @t )
Select ProjectId,EmployeeId,TotalDays
From Cte Where Rn = 1

结果

ProjectId   EmployeeId  TotalDays
1            100        10
1            200        10

对于员工ID=200，项目ID=2？？？对不起，所有员工的项目ID都是相同的。我只是按照序列号，项目ID为1表示所有否，项目ID为1表示所有员工。抱歉，我打错了。如果是这种情况，并且您想包括项目ID，
选择ProjectID，EmployeeID，SUM（totalDays）tableName组中按ProjectID、EmployeeID的totalDays，您可以进一步修改为此。