SQL語句連接表是空查詢

Question

你好我使用的是加入表查詢來獲取一些數據..

USE [AccountingSystem_TEST] 
GO 
/****** Object: StoredProcedure [dbo].[spHRLeaveEntitlementBuildTemp] Script Date: 03/14/2013 09:18:06 ******/ 
SET ANSI_NULLS ON 
GO 
SET QUOTED_IDENTIFIER ON 
GO 

ALTER Procedure [dbo].[spHRLeaveEntitlementBuildTemp] 
    ( 
    @CreatedUserID as nvarchar(9) 
    ,@EmployeeID nvarchar(9) 
    ,@EmpName nvarchar(150) 
    ) 
AS 
BEGIN 

    Select A.CodeHRLeaveType, 
     COALESCE(B.LeaveBalance) LeaveBalance   
    From HRLeaveType A 
     LEFT JOIN HRLeaveMaster B 
     On A.CodeHRLeaveType = B.CodeHRLeaveType 
    Where B.EmployeeID = @EmployeeID 

    Delete dbo.HrLeaveMasterTemp 
    Where UserID = @CreatedUserID 

    INSERT INTO [dbo].[HrLeaveMasterTemp] 
     ([UserID] 
     ,[EmployeeID] 
     ,[EmpName] 
     ,[CodeHRLeaveType] 
     ,[LeaveBalance] 
     ,[Status] 
     ) 
    Select 
     @CreatedUserID    
     ,[EmployeeID] 
     ,@EmpName 
     ,[CodeHRLeaveType] 
     ,[LeaveBalance] 
     ,[Status]   
    From dbo.[HRLeaveMaster] 
    Where EmployeeID =@EmployeeID 
END 
--Select * From HRLeaveMasterTemp 

如果leavebalance爲null，我需要的表格顯示0 ..但聲明顯示錯誤。請幫助我..

Answer 1

使用COALESCE

Select A.CodeHRLeaveType, 
     COALESCE(B.LeaveBalance) LeaveBalance   
From HRLeaveType A 
     LEFT JOIN HRLeaveMaster B 
      On A.CodeHRLeaveType = B.CodeHRLeaveType 
Where B.EmployeeID = @EmployeeID 

Answer 2

在甲骨文更換空函數的使用與NVL功能。在MySql中使用 替換null函數與IFNULL函數一起使用。請致電http://www.w3schools.com/sql/sql_isnull.asp。這可能會幫助你。

的說法應該是 -

Select A.CodeHRLeaveType, 
    IFNULL(B.LeaveBalance,0) LeaveBalance   
From HRLeaveType A 
    LEFT JOIN HRLeaveMaster B 
    On A.CodeHRLeaveType = B.CodeHRLeaveType 
Where B.EmployeeID = @EmployeeID