SQL 传统加入

Question

我正在查看一些较旧的 SQL 代码，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

*= 几乎加入了更新语法中的 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

SQL 传统加入

SQL Legacy Joins

sql

tsql

syntax

outer-join