Question

请帮助查询

我的Student_Master Table： -

ID Name  
1  AAA
2  BBB  
3  CCC
4  DDD

My Student Details Table

ID MastID Address
1   1     Address 1   
2   2     Address 2

现在我有一个绑定到学生主表格的gridview，现在我想在我的gridview中调用一个自定义列，以便“那里有地址的学生应该是”Address Present“，而对于地址不是的学生在表中显示他们的状态将是“地址不存在” 例如。

ID Name  Status
1  AAA   Address Present
2  BBB   Address Present 
3  CCC   Address NOT Present  
4  DDD  Address NOT Present

Answer 1

试试这个：

SELECT
    M.ID, 
    M.Name,
    CASE WHEN D.Id IS NULL
         THEN 'Address NOT Present'
         ELSE 'Address Present'
    END Status
FROM Master M
    LEFT JOIN Details D
        ON M.Id = D.MastID

QUERY sql数据库

1 个答案: