將多個結果合併到一個列表中

Question

我有兩個表，稱爲請求和請求關係，詳情如下。

要求

reqId regNum desc 
12  111 Tomato 
13  112 Carrot 
14  113 Chilli 
15  114 Onion 
16  115 Garlic 

requestRelationship

reqID relatedRequestId 
12  14 
12  16 
13  14 
13  15 

什麼，我想顯示類似下面的信息

reqId regNum desc relateRequest 
12  111 Tomato 113,115 
13  112 Carrot 113,114 

目前我只有基本的曲ERY

select r.reqId, r.reqNum, r.desc, relateRequest = STUFF((select Distinct ', ' + regNum from request b where b.reqId = a.reqId FOR XML PATH (' ')), 1, 2, '') 
from request r 
INNER JOIN requestRelationship t WITH (NOLOCK) on r.reqID = t.reqID 
order by r.reqId desc 

Answer 1

你STUFF基本需要加入您的request表上relatedrequestid（而你的外部查詢是在reqID加盟），所以你的整個選擇應該是這個樣子：

SELECT DISTINCT R.reqID, R.regNum, R.[desc], 
     relateRequest = STUFF(
      (SELECT DISTINCT ', ' + CAST(R2.regNum AS VARCHAR(10)) 
      FROM request AS R2 
      JOIN requestRelationship AS RR2 
       ON RR2.relatedrequestid = R2.reqID 
      WHERE RR2.ReqID = RR.ReqID -- This joins to your outer query. -- You can also join on R.ReqID, doesn't make a difference. 
      FOR XML PATH ('')), 1, 2, '') 
FROM request AS R 
JOIN requestRelationship AS RR 
    ON RR.reqID = R.reqID;