Sql server 2005 向T-sql左外部联接查询添加where子句时出现问题

我想要的基本功能是检索表dbo.EmployeeInfo中的所有记录，而不管表dbo.EmployeeInfo中是否存在相应的记录。如果EmployeeInfo中的一行在LeaveApplications中没有相关行，我希望将其SUMdbo.LeaveApplications.DaysaoAuthorized AS DaysTaken列返回为NULL，或者甚至可以将其置为0

通过上面的查询，如果我删除where条件，我就能够实现我想要的，但问题是，我还希望仅当ApplicationDate在当前年份时，才从LeaveApplication返回相关行

现在添加了where条件，我只能从EmployeeInfo中获取行，前提是它们在LeaveApplications中有相应的行，但我只希望EmployeeInfo中的行都是行。您可以在where子句中添加NULL测试，这可能会导致您的总和对于LeaveApplications表中不存在的行也返回NULL：

---

如果没有相应的应用程序，您希望发生什么？对于返回的行，它应该在where子句中执行什么操作？如果没有LeaveApplications，我仍然希望返回EmployeeInfo中的所有行，然后为dbo.LeaveApplications.DaysaoAuthorized查询结果列指定一个NULL值甚至0。可能是我应该添加，即使LeaveApplications中有0个相关行，我仍然希望检索EmployeeInfo中的所有记录，然后为每个返回行的DaysauAuthorized列显示0。

SELECT TOP (100) PERCENT dbo.EmployeeInfo.id, MIN(dbo.EmployeeInfo.EmpNo) AS EmpNo, 
            SUM(dbo.LeaveApplications.DaysAuthorised) AS DaysTaken
FROM  dbo.EmployeeInfo LEFT OUTER JOIN dbo.LeaveApplications ON 
           dbo.EmployeeInfo.id = dbo.LeaveApplications.EmployeeID
WHERE (YEAR(dbo.LeaveApplications.ApplicationDate) = YEAR(GETDATE()))
GROUP BY dbo.EmployeeInfo.id, dbo.EmployeeMaster.EmpNo
ORDER BY DaysTaken DESC 

SELECT TOP (100) PERCENT dbo.EmployeeInfo.id, MIN(dbo.EmployeeInfo.EmpNo) AS EmpNo, 
            SUM(dbo.LeaveApplications.DaysAuthorised) AS DaysTaken
FROM  dbo.EmployeeInfo LEFT OUTER JOIN dbo.LeaveApplications ON 
           dbo.EmployeeInfo.id = dbo.LeaveApplications.EmployeeID
WHERE (YEAR(dbo.LeaveApplications.ApplicationDate) = YEAR(GETDATE()))
      OR dbo.LeaveApplications.ApplicationDate IS NULL
GROUP BY dbo.EmployeeInfo.id, dbo.EmployeeMaster.EmpNo
ORDER BY DaysTaken DESC