sql-server-2008 - sql server 2008中的内连接

Question

我想从 3 个表中选择值，我为此使用内连接，我正在使用以下查询

  SELECT 
    UserDetail.UserId 'userId', 
    FirstName  'name',  
    Name 'role' 
    FROM UserDetail as ud 
       inner join UserRole as ur ON ud.UserId = ur.UserId 
       inner join [Role] as r ON r.RoleId=ur.RoleId 
       WHERE Username = @username and [Password] =@password 

它向我显示以下错误：无法绑定多部分标识符 UserId（UserDetail.UserId）。谁能告诉我我做错了什么。谢谢

Answer 1

替换UserDetail.UserId为ud.UserId。如果您UserDetail as ud在子句中使用别名 ( )，FROM您也必须在其他任何地方使用相同的别名。

Answer 2

替换你UserDetail.UserId的ud.UserId

IE：

SELECT 
    ud.UserId 'userId', 
    FirstName  'name',  
    Name 'role' 
    FROM UserDetail as ud 
       inner join UserRole as ur ON ud.UserId = ur.UserId 
       inner join [Role] as r ON r.RoleId=ur.RoleId 
       WHERE Username = @username and [Password] =@password