下面这条sql语句怎样用内连接或者外连接实现，我是菜鸟，求指导！谢谢啦~很急

发布网友发布时间：2022-04-27 07:58

共3个回答

热心网友时间：2023-10-02 14:14

string sql = "select Users.* ,Card.IsReportLost from Users,Card,Departments where Users.CardID = Card.CardID and Users.DeptID = Departments.ID";

select Users.*,Card.IsReportLost from Users join Card on Users.CardID = Card.CardID join Departments on Users.DeptID = Departments.ID

热心网友时间：2023-10-02 14:15

select Users.* ,Card.IsReportLost from Users
left join Card on (Users.CardID = Card.CardID)
left join Departments on (Users.DeptID = Departments.ID)

热心网友时间：2023-10-02 14:15

string sql = "select Users.*,Card.IsReportLost from Users
left join Card on Users.CardID = Card.CardID
left join Departments on Users.DeptID = Departments.ID";

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