SQL查询 - 多个连接在同一字段

Question

我需要帮助建立此查询，我需要从同一表中选择不同的值，但不同的唯一键。

更详细地说明病人提供下面的例子：

我有2个表：

问题（IssueID，AuthorID_FK，AssigedID_FK，...）
用户（用户ID，User_Label，.. 。）

两个AuthorID_FK & AssigedID_FK AR e链接到表用户和我需要得到相同的查询结果User_Label两者。

您能否协助？

感谢，

Answer 1

SELECT a.IssueID, b.User_Label, c.User_Label FROM Issues a 
INNER JOIN USERS b on a.AuthorID_FK = b.UserID 
INNER JOIN USERS c on a.AssignedID_FK = c.UserID 

类似的东西:)这应该在MS SQL服务器

Answer 2

很好地工作，这应该工作太:)

SELECT IssueID, U.User_Label FROM Issues I 
INNER JOIN Users U ON U.UserID = I.AuthorID_FK 

UNION 

SELECT IssueID, U.User_Label FROM Issues I 
INNER JOIN Users U ON U.UserID = I.AssigedID_FK 

Answer 3

惯于

SELECT a.IssueID, b.UserID 
FROM Issues a 
    JOIN Users b ON (a.AuthorID_FK=b.UserID OR a.AssignedID_FK = b.UserID) 

工作？

Answer 4

你可能想尝试这样的事情

SELECT 
    issues.IssueID, 
    Authour.User_Label AS Author_Label, 
    Assigned.User_Label AS Assigned_user_Label 
FROM 
    issues 
    INNER JOIN users AS Authour ON Authour.UserID = issues.AuthorID_FK 
    INNER JOIN users AS Assigned ON Assigned.UserID = issues.AssignedID_FK