Question

以此示例查询：

INSERT INTO #QueryOutput 
   SELECT DISTINCT 
      UR2.LeftID, UR3.LeftID  
   FROM 
      UserRelations UR1 
   JOIN 
      UserRelations UR2 ON UR1.RightID =  UR2.LeftID 
   JOIN 
     UserRelations UR3 ON UR2.RightID =  UR3.LeftID  
   WHERE 
     (UR1.RelationID = 1) 
     OR (UR1.RelationID = 1 AND UR2.RelationID = 1) 
     AND UR1.LeftID IN (SELECT UserID FROM #QueryInput)

这是魔术行：

INSERT INTO #QueryOutput SELECT DISTINCT UR2.LeftID ,UR3.LeftID

#QueryOutput是一个包含单个列的表，UserID

我希望在该单个列中插入UR2.LeftID，UR3.LeftID或尽可能多的UR*.LeftID。怎么办呢？

由于

Answer 1

如果您使用的是SQL Server 2008或更高版本，我认为最好的方法是使用cross apply和table valued constructor进行取消操作：

INSERT INTO #QueryOutput 
SELECT  DISTINCT upvt.LeftID
FROM    UserRelations UR1 
        JOIN UserRelations UR2 
            ON UR1.RightID =  UR2.LeftID 
        JOIN UserRelations UR3 
            ON UR2.RightID =  UR3.LeftID
        CROSS APPLY (VALUES (UR2.LeftID), (UR3.LeftID )) AS upvt (LeftID)
WHERE   (UR1.RelationID = 1 ) 
OR      (UR1.RelationID = 1 AND UR2.RelationID = 1 ) 
AND     UR1.LeftID IN (SELECT UserID FROM #QueryInput)

Answer 2

也许这就是你想要的：

INSERT INTO #QueryOutput
    SELECT DISTINCT (case when n.n = 2 then UR2.LeftID 
                          when n.n = 3 then UR3.LeftID
                     end)
    FROM UserRelations UR1 JOIN
         UserRelations UR2
         ON UR1.RightID =  UR2.LeftID JOIN
         UserRelations UR3
         ON UR2.RightID =  UR3.LeftID CROSS JOIN
         (select 2 as n union all select 3) n 
    WHERE (UR1.RelationID = 1 ) OR (UR1.RelationID = 1 AND UR2.RelationID = 1 ) AND
          UR1.LeftID IN (SELECT UserID FROM #QueryInput);

Answer 3

除非您尝试执行下面的UNION ALL

，否则您无法做到这一点

INSERT INTO #QueryOutput

SELECT DISTINCT UR2.LeftID FROM UserRelations UR1 
JOIN UserRelations UR2 ON UR1.RightID =  UR2.LeftID 
JOIN UserRelations UR3 ON UR2.RightID =  UR3.LeftID  WHERE (UR1.RelationID = 1 ) 
OR (UR1.RelationID = 1 AND UR2.RelationID = 1 ) 
AND UR1.LeftID IN (SELECT UserID FROM #QueryInput)

UNION ALL

SELECT DISTINCT UR3.LeftID FROM UserRelations UR1 
JOIN UserRelations UR2 ON UR1.RightID =  UR2.LeftID 
JOIN UserRelations UR3 ON UR2.RightID =  UR3.LeftID  WHERE (UR1.RelationID = 1 ) 
OR (UR1.RelationID = 1 AND UR2.RelationID = 1 ) 
AND UR1.LeftID IN (SELECT UserID FROM #QueryInput)

在临时表的单个列中插入单行值

3 个答案: