Question

我正在开发一个类似于FB的项目。所以我有朋友（存储在“请求”中，通过在2个用户之间请求“响应”为1.我也有“圈子”，就像朋友组。我想要的是一个SELECT，它返回所有朋友而不是在一个给定的圈子里。我相信查询是正确的，直到“AND NOT”，此时我想要排除所有请求（朋友），其中包含发送者或接收者（我知道拼写错误）已经包含在圈子中。

SELECT us.Username ,
       ur.Username
FROM Requests r 
Join Users    us ON us.UserID = r.Sender 
JOIN Users    ur ON ur.UserID = r.Reciever 
WHERE (    Sender   = ( SELECT UserID
                        FROM Users
                        WHERE Username=?
                      ) 
        OR Reciever = ( SELECT UserID
                        FROM Users
                        WHERE Username = ?
                      )
      ) 
  AND Response=1 
  AND NOT ON ( SELECT un.Username
               FROM CircleMembers c 
               Join Users         un ON un.UserID = c.UserID 
               WHERE CircleID = ( SELECT CircleID
                                  FROM Circles WHERE Name = ?
                                )

谢谢！

Answer 1

此查询应该有效：

SELECT us.Username, ur.Username 
FROM Requests r 
Join Users us ON us.UserID = r.Sender 
JOIN Users ur ON ur.UserID = r.Reciever
WHERE (us.Username = ? OR ur.Username = ?)
  AND r.Response = 1
  AND NOT EXISTS (
    SELECT 1 FROM Circles c
    JOIN CircleMembers cm ON c.CircleID = cm.CircleID
    WHERE c.Name = ?
    AND cm.UserID IN (us.UserID, ur.UserID)
  )

Answer 2

尝试：

AND column_name NOT IN (SELECT column_name FROM table_name WHERE...)

从SQL Query中排除一些结果

2 个答案: