SQL查詢 - 多個連接在同一字段

Question

我需要幫助建立此查詢，我需要從同一表中選擇不同的值，但不同的唯一鍵。

更詳細地說明病人提供下面的例子：

我有2個表：

問題（IssueID，AuthorID_FK，AssigedID_FK，...）
用戶（用戶ID，User_Label，.. 。）

兩個AuthorID_FK & AssigedID_FK AR e鏈接到表用戶和我需要得到相同的查詢結果User_Label兩者。

您能否協助？

感謝，

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 

類似的東西:)這應該在MS SQL服務器

Answer 2

很好地工作，這應該工作太:)

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

慣於

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

你可能想嘗試這樣的事情

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