找到從查詢中找到的值的總和

Question

您好我有一個查詢返回兩行數據作爲計數。我想找到列值的總和。我的SQL：

(SELECT count(memberid) count 
    FROM `friendRequest`, Member 
    where status = 2 and memberid = sender and receiver = 19) 
UNION 
(SELECT count(memberid) count 
    FROM `friendRequest`, Member 
    where status = 2 and memberid = receiver and sender = 19) 

我一直在使用SELECT SUM（我上面的查詢），但我得到的錯誤嘗試。有人可以幫幫我嗎。我只需要一些以上的值。

問候 潘卡

Answer 1

可以抓取兩個結果集中在一個單一的查詢：

SELECT count(memberid) count 
FROM `friendRequest`, Member 
WHERE status = 2 AND (
    (memberid = sender AND receiver = 19) OR 
    (memderid = receiver AND sender = 19) 
) 

Answer 2

嘗試：

SELECT SUM(count) 
FROM 
    ...the rest of your query... 

Answer 3

如果你要使用的聚集，需要組它通過使用東西GROUP BY

(SELECT count(memberid) SUM(count) 
    FROM `friendRequest`, Member 
    where status = 2 and memberid = sender and receiver = 19 
    GROUP BY Member) 
UNION 
(SELECT count(memberid) SUM(count) 
    FROM `friendRequest`, Member 
    where status = 2 and memberid = receiver and sender = 19 
    GROUP BY Member) 

Answer 4

繼將正常運行是

SELECT SUM(count) 
FROM (
     (SELECT count(memberid) count 
      FROM `friendRequest`, Member 
      where status = 2 and memberid = sender and receiver = 19) 
      UNION 
     (SELECT count(memberid) count 
      FROM `friendRequest`, Member 
      where status = 2 and memberid = receiver and sender = 19) 
     ) AS anyAliasWillDo 

，但我強烈建議你停止使用隱式連接（過時）並開始使用顯式連接語法。聲明然後變成

SELECT SUM(COUNT) 
FROM (
      SELECT COUNT(memberid) AS COUNT 
      FROM `friendRequest` AS fr 
        INNER JOIN Member AS m ON m.memberid = fr.sender 
      WHERE status = 2 AND receiver = 19 
      UNION ALL 
      SELECT COUNT(memberid) AS COUNT 
      FROM `friendRequest` AS fr 
        INNER JOIN Member AS m ON m.memberid = fr.receiver 
      WHERE status = 2 AND sender = 19 
     ) AS AnyAliasWillDo