Question

我正在尝试加入这些表并且有一个Sum值，但它没有显示任何错误，但是它的值是错误的...但是如果我加入两个表它正常工作。

查询

SELECT  tblEmployeeInfo.EmpCode, 
        SUM(tblLeave.lvDay) AS Total, 
        tblAtData.card_no

FROM    tblEmployeeInfo 
INNER JOIN tblLeave ON tblEmployeeInfo.EmpCode = tblLeave.lvEmpId 
INNER JOIN tblAtData ON tblEmployeeInfo.EmpCardID = tblAtData.card_no

WHERE  (tblLeave.lvMonth = @month)

GROUP BY tblEmployeeInfo.EmpCode, tblAtData.card_no

Answer 1

您应该在tblLeave的子查询中计算SUM，然后在JOIN表中计算：

  SELECT   tblEmployeeInfo.EmpCode, 
            tblLeave.SUMlvDays AS Total, 
            tblAtData.card_no

    FROM    tblEmployeeInfo 
    INNER JOIN 
        (select lvEmpId, SUM(lvDay) as SUMlvDays 
                    from  tblLeave 
          WHERE  (tblLeave.lvMonth = @month)
         group by lvEmpId )  tblLeave

           ON   tblEmployeeInfo.EmpCode = tblLeave.lvEmpId 

    INNER JOIN tblAtData ON tblEmployeeInfo.EmpCardID = tblAtData.card_no
    GROUP BY tblEmployeeInfo.EmpCode, tblAtData.card_no

Answer 2

SELECT   tblEmployeeInfo.EmpCode, 
        tblLeave.SUMlvDays AS Total, 
        tblAtData.card_no

FROM    tblEmployeeInfo 
INNER JOIN 
    (select lvEmpId, SUM(lvDay) as SUMlvDays 
                from  tblLeave 
      WHERE  (tblLeave.lvMonth = @month)
     group by lvEmpId )  tblLeave

       ON   tblEmployeeInfo.EmpCode = tblLeave.lvEmpId 

INNER JOIN tblAtData ON tblEmployeeInfo.EmpCardID = tblAtData.card_no
GROUP BY tblEmployeeInfo.EmpCode, tblAtData.card_no,tblLeave.SUMlvDays

查询连接三个表与Sum

2 个答案: