Sql 使用外部应用返回空值

我有以下表格：

具有主键和用户名的用户，例如

ID Username 1 Fred 2 John 3 Jack

---

如何找回可能未进行更新的用户？

您的查询有多个where子句，并且您已经指定了

UserStatusUpdates.UserID=users.users\u ID

加入子查询。试试这个：

SELECT 
  EventAttendee.*, 
  Users.UserName,Users.USERS_ID, 
  Users.ThumbnailPic,
  Users.CountryName,
  ISNULL(UserStatusUpdates.UserStatus,'No Updates') AS LastUpdate,
  UserStatusUpdates.MediaTypeID,
  UserStatusUpdates.USERSTATUS_ID,
  UserStatusUpdates.AddDate
FROM 
  EventAttendee
  JOIN Users ON 
    Events.UserID = Users.USERS_ID
  OUTER APPLY (
    SELECT TOP 1 
      UserStatusUpdates.UserStatus,
      UserStatusUpdates.MediaTypeID,
      UserStatusUpdates.USERSTATUS_ID,
      UserStatusUpdates.AddDate,
      UserStatusUpdates.UserID
    FROM 
      UserStatusUpdates  
    WHERE 
      UserStatusUpdates.UserID = Users.USERS_ID
    ORDER BY 
      AddDate DESC
  ) AS UserStatusUpdates 
WHERE 
  EventAttendee.EventID = @EventID 
  AND Users.bDeleted = 'False' 
  AND Users.bSuspended =  'False'
END 

---

我不明白背靠背的位置-WHERE TempUserStatusUpdates.UserID=EventAttendee.UserID WHERE EventAttendee.EventID=@EventIDSorry这是一个错误，我已将其改回UserStatusUpdates。哇，非常感谢您的帮助，我一直在努力解决这个问题。再次非常感谢你的帮助。 ID UserID UserStatus 1 1 Really Good 2 1 Leaving Now 3 2 I concur ID UserID EventID 1 1 1 2 2 1 3 3 1

SELECT EventAttendee.*, Users.UserName,Users.USERS_ID, 
Users.ThumbnailPic,
Users.CountryName,
ISNULL(UserStatusUpdates.UserStatus,'No Updates')AS LastUpdate,
UserStatusUpdates.MediaTypeID,UserStatusUpdates.USERSTATUS_ID,(UserStatusUpdates.AddDate)

FROM EventAttendee
JOIN Users ON Events.UserID = Users.USERS_ID
OUTER APPLY  (SELECT TOP 1 UserStatusUpdates.UserStatus,UserStatusUpdates.MediaTypeID,
UserStatusUpdates.USERSTATUS_ID,UserStatusUpdates.AddDate, UserStatusUpdates.UserID
  FROM UserStatusUpdates  where UserStatusUpdates.UserID = Users.USERS_ID
ORDER BY AddDate DESC) AS UserStatusUpdates WHERE UserStatusUpdates.UserID = EventAttendee.UserID

WHERE EventAttendee.EventID = @EventID 
AND Users.bDeleted = 'False' 
AND Users.bSuspended =  'False'
END 

SELECT 
  EventAttendee.*, 
  Users.UserName,Users.USERS_ID, 
  Users.ThumbnailPic,
  Users.CountryName,
  ISNULL(UserStatusUpdates.UserStatus,'No Updates') AS LastUpdate,
  UserStatusUpdates.MediaTypeID,
  UserStatusUpdates.USERSTATUS_ID,
  UserStatusUpdates.AddDate
FROM 
  EventAttendee
  JOIN Users ON 
    Events.UserID = Users.USERS_ID
  OUTER APPLY (
    SELECT TOP 1 
      UserStatusUpdates.UserStatus,
      UserStatusUpdates.MediaTypeID,
      UserStatusUpdates.USERSTATUS_ID,
      UserStatusUpdates.AddDate,
      UserStatusUpdates.UserID
    FROM 
      UserStatusUpdates  
    WHERE 
      UserStatusUpdates.UserID = Users.USERS_ID
    ORDER BY 
      AddDate DESC
  ) AS UserStatusUpdates 
WHERE 
  EventAttendee.EventID = @EventID 
  AND Users.bDeleted = 'False' 
  AND Users.bSuspended =  'False'
END