SQL Legacy加入

Question

我正在查看一些较旧的SQL代码，并且我想知道将此批处理转换为当前SQL语法的正确方法是什么。感谢您的帮助。

    If @Type = 'Edit'  
    Begin
        If @Area = 'Box'
            Declare CursorInv Cursor For 
                Select Retention_Code, 
                    Company_Id, 
                    Department_Id, 
                    Group_Id, 
                    Section_Id, 
                    Locator_Id, 
                    Location_Current, 
                    Location_Home, 
                    Box_User_Defined1.Udf_Code User_Defined1, 
                    Box_User_Defined2.Udf_Code User_Defined2, 
                    Box_User_Defined3.Udf_Code User_Defined3
        From Box, Box_User_Defined1, Box_User_Defined2, Box_User_Defined3
        Where Box_Number = @KeyValue And 
                Box.User_Defined1 *= Box_User_Defined1.ID And 
                Box.User_Defined2 *= Box_User_Defined2.ID And 
                Box.User_Defined3 *= Box_User_Defined3.ID

Answer 1

*=在较新的语法中加入了LEFT JOIN：

SELECT Retention_Code, 
    Company_Id, 
    Department_Id, 
    Group_Id, 
    Section_Id, 
    Locator_Id, 
    Location_Current, 
    Location_Home, 
    Box_User_Defined1.Udf_Code User_Defined1, 
    Box_User_Defined2.Udf_Code User_Defined2, 
    Box_User_Defined3.Udf_Code User_Defined3
FROM Box
LEFT JOIN Box_User_Defined1 ON Box.User_Defined1 = Box_User_Defined1.ID
LEFT JOIN Box_User_Defined2 ON Box.User_Defined2 = Box_User_Defined2.ID
LEFT JOIN Box_User_Defined3 ON Box.User_Defined3 = Box_User_Defined3.ID
WHERE Box_Number = @KeyValue