DISTINCT行的字段总和

Question

我希望能够在不同的行ID上获得字段“count”的总和。

以下是我对它的查询。我们怎样才能做到这一点？

SELECT l.sid, l.Title, u.CompanyName, l.activation_date, l.expiration_date, COUNT(s.count), COUNT(DISTINCT a.id) 
      FROM listings l 
      LEFT JOIN statistics s 
      ON s.object_sid = l.sid 
      LEFT JOIN users u 
      ON u.sid = l.user_sid 
      LEFT JOIN applications a 
      ON a.listing_id = l.sid 
      WHERE l.sid = 6276 
      AND s.event = 'viewListing' 
      GROUP BY l.sid 
      LIMIT 10 

Answer 1

如果通过“上市”和“应用程序”需要的列statistics.count的总和，那么你就需要GROUP BY都“挂牌”和“应用”：

SELECT 
    l.sid, l.Title, l.activation_date, l.expiration_date, 
    u.CompanyName, 
    SUM(s.count), COUNT(a.id) -- <= SUM(s.count) 
FROM listings l 
LEFT JOIN statistics s ON s.object_sid = l.sid 
LEFT JOIN users u ON u.sid = l.user_sid 
LEFT JOIN applications a ON a.listing_id = l.sid 
WHERE l.sid = 6276 
AND s.event = 'viewListing' 
GROUP BY l.sid, a.sid -- <= GROUP BY clause modified