Question

我想在查询中使用两个表，tblEmployee和tblEmpPerformance

要求是：

使用tblEmployee.EmpID, tblEmployee.ManagerID，直到tblEmpPerformance并查看tblEmpPerformance.SalaryRaise和tblEmpPerformance.CommissionRaise，并相应地更新tblEmployee。

对于tblEmpPerformance

中的每条记录，这两个字段中只有一个字段的值为非零值

if tblEmployee.EmpID = tblEmpPerformance.EmpID then 
If tblEmpPerformance.Salary > 0 then
    update tblEmployee
    Set CompensationType = 'Salary'
    Where tblEmployee.EmpID = tblEmpPerformance.EmpID 
    AND tblEmployee.ManagerID = tblEmpPerformance.ManagerID   

    update tblEmployee
    Set SalaryRaise = tblEmpPerformance.SalaryRaise
    Where tblEmployee.EmpID = tblEmpPerformance.EmpID 
    AND tblEmployee.ManagerID = tblEmpPerformance.ManagerID 

If tblEmpPerformance.Commission > 0 then
    update tblEmployee
    Set CompensationType = 'Commission'
    Where tblEmployee.EmpID = tblEmpPerformance.EmpID 
    AND tblEmployee.ManagerID = tblEmpPerformance.ManagerID 

    update tblEmployee
    Set CommissionRaise = tblEmpPerformance.CommissionRaise
    Where tblEmployee.EmpID = tblEmpPerformance.EmpID 
    AND tblEmployee.ManagerID = tblEmpPerformance.ManagerID

如果找不到匹配的EmpID，请查看tblContractorPerformance

if tblEmployee.EmpID = tblContractorPerformance.EmpID then 
    If tblContractorPerformance.Salary > 0 then
    update tblEmployee
    Set CompensationType = 'Salary'
    Where tblEmployee.EmpID = tblContractorPerformance.EmpID 
    AND tblEmployee.ManagerID = tblContractorPerformance.ManagerID 
    ....
    ....
    ....
    ....

Next tblEmployee.EmpID

更新： DOH !! 编写此SQL查询的最佳方法是什么。存储过程或光标？任何关于如何设计查询的建议都将是一个很好的帮助

Answer 1

据我所知，您可以将其封装到一个查询中：

Update tblEmployee
Set CompensationType = Case
                        When EP.Commission > 0 Then 'Commission'
                        When EP.Salary > 0 Then 'Salary'
                        When CP.Salary > 0 Then 'Salary'
                        Else E.CompensationType -- leave value as is
                        End
    , CommissionRaise = Case
                        When EP.Commission > 0 Then EP.CommissionRaise
                        Else E.CommissionRaise -- leave value as is
                        End
    , SalaryRaise = Case
                        When EP.Commission > 0 Then E.SalaryRaise
                        When EP.Salary > 0 Then EP.SalaryRaise
                        When CP.Salary > 0 Then CP.SalaryRaise
                        Else E.SalaryRaise -- leave value as is
                        End
From tblEmployee As E
    Left Join tblEmployeePerformance As EP
        On EP.EmpID = E.EmpID
            And EP.ManagerId = E.ManagerId
    Left Join tblContractorPerformance As CP
        On CP.EmpID = E.EmpID
            And CP.ManagerId = E.ManagerId

Answer 2

请避免使用游标。在处理数据时考虑基于集合。因此，执行第一组数据，tblEmpPerformance.Salary > 0。进行更新，然后对tblEmpPerformance.Commission > 0的下一组数据执行第二次操作。最后，更新tblContractorPerformance.Salary > 0。

所有数据

将这些操作放在存储过程中，我相信你会看到比使用游标等效的更好的性能。

又一个复杂的SQL 2000查询问题

2 个答案: