SELECT语句别名上的无效对象名称错误

Question

我编写了一个SQL查询，该查询为两个嵌套的SELECT语句中的每一个分配别名，并尝试加入这些别名。

我的SQL查询如下：

SELECT EmpID,
       (SELECT EmpID
              ,Count(*) * 8 AS [FullDayHours]
        FROM [database].[dbo].[tblLogTimes] 
        WHERE ActivityID = 43 
        AND WorkDate BETWEEN '2015-12-31 00:00:00.000' AND '2016-09-30 00:00:00.000'
        GROUP BY EmpID) AS [Rec1]
      ,(SELECT EmpID
              ,(Count(*) * 4) AS [HalfDayHours] 
        FROM [database].[dbo].[tblLogTimes] 
        WHERE ActivityID = 44 
        AND WorkDate BETWEEN '2015-12-31 00:00:00.000' AND '2016-09-30 00:00:00.000'
        GROUP BY EmpID) AS [Rec2]
FROM [database].[dbo].[tblLogTimes] E
INNER JOIN [Rec1] ON E.EmpID = [Rec1].EmpID
INNER JOIN [Rec2] ON E.EmpID = [Rec2].EmpID

尝试执行查询时，出现错误：无效的对象名称'Rec1'。

我已经尝试了查询组件子语句的各种安排和配置，但无济于事。

有见识，建议将非常受欢迎。 感谢您的光临。

Answer 1

我相信这是您想要的，而不是将子查询移至join ：

SELECT EmpID, FullDayHours, HalfDayHours
FROM [StaffSuite].[dbo].[tblLogTimes] E
INNER JOIN (SELECT EmpID
              ,Count(*) * 8 AS [FullDayHours]
        FROM [StaffSuite].[dbo].[tblLogTimes] 
        WHERE ActivityID = 43 
        AND WorkDate BETWEEN '2015-12-31 00:00:00.000' AND '2016-09-30 00:00:00.000'
        GROUP BY EmpID) AS [Rec1] ON E.EmpID = [Rec1].EmpID
INNER JOIN (SELECT EmpID
              ,(Count(*) * 4) AS [HalfDayHours] 
        FROM [StaffSuite].[dbo].[tblLogTimes] 
        WHERE ActivityID = 44 
        AND WorkDate BETWEEN '2015-12-31 00:00:00.000' AND '2016-09-30 00:00:00.000'
        GROUP BY EmpID) AS [Rec2] ON E.EmpID = [Rec2].EmpID

---

但是，您可以使用conditional aggregation来进一步简化它：

SELECT EmpID, FullDayHours, HalfDayHours
FROM [StaffSuite].[dbo].[tblLogTimes] E
INNER JOIN (SELECT EmpID
              ,Count(case when activityid = 43 then 1 end) * 8 AS [FullDayHours]
              ,Count(case when activityid = 44 then 1 end) * 4 AS [HalfDayHours]
        FROM [StaffSuite].[dbo].[tblLogTimes] 
        WHERE ActivityID IN (43,44)
        AND WorkDate BETWEEN '2015-12-31 00:00:00.000' AND '2016-09-30 00:00:00.000'
        GROUP BY EmpID) AS [Rec1] ON E.EmpID = [Rec1].EmpID