将同一个表连接到多个字段

Question

我有这个 SQL，我正在尝试将人员登录名表加入到包含多个用户 ID 的任务表中，

  SELECT Task.TaskID
      ,Project.Project
      ,Task.Task
      ,Task.Description
      ,Task.OwnerLoginID //shown as Login.UserName
      ,Task.SubmitterID //shown as Login.UserName
      ,Task.IsVisible
  FROM Task
  INNER JOIN Project ON Task.ProjectID = Project.ProjectID
  /*
  INNER JOIN Login ON Task.SubmitterID = Login.LoginID
  INNER JOIN Login ON Task.OwnerLoginID = Login.LoginID
  */
  WHERE IsVisible = 1

但在底部的注释行中出现错误，我哪里出错了？

Answer 1

尝试为表分配别名，例如

SELECT Task.TaskID
      ,Project.Project
      ,Task.Task
      ,Task.Description
      ,submitted.UserName
      ,owner.UserName
      ,Task.IsVisible
  FROM Task
  INNER JOIN Project ON Task.ProjectID = Project.ProjectID
  INNER JOIN Login submitted ON Task.SubmitterID = submitted.LoginID
  INNER JOIN Login owner ON Task.OwnerLoginID = owner.LoginID
  WHERE IsVisible = 1

Answer 2

如果你想 JOIN 同一张桌子意味着，像这样给予

  INNER JOIN Login L ON Task.SubmitterID = L.LoginID
  INNER JOIN Login LA ON Task.OwnerLoginID = LA.LoginID