Question

我需要一点帮助来简化我的mysql查询。我有三张桌子。一个用于主要用户记录，第二个用于每个用户的奖励积分（每个用户多个记录），第三个用于结果点（每个用户多个记录）。

QUERY

SELECT u.*, (SELECT SUM(ub.Points) 
FROM nba_user_bonus AS ub 
WHERE ub.UserId = u.Id) AS BonusPoints,  
(SELECT SUM(ur.Points) 
FROM nba_user_result AS ur 
WHERE ur.UserId = u.Id) AS ResultPoints 
FROM nba_users AS u 
WHERE u.Status = 'Enable' 
ORDER BY u.Id ASC

这里我给每个用户提供总奖励积分和总积分，但是我需要通过TotalPoints DESC为每个用户订单设置TatalPoint（结果点和奖励积分的总和）。在排序中，我想要用户名单以获得排行榜的积分请问我是否需要db表的任何进一步细节。希望得到你的帮助。

Answer 1

您的查询是合理的。您可以将两个值一起添加：

SELECT u.*,
       ((SELECT SUM(ub.Points) FROM nba_user_bonus ub  WHERE ub.UserId = u.Id) + 
        (SELECT SUM(ur.Points) FROM nba_user_result ur WHERE ur.UserId = u.Id)
       ) as TotalPoints
FROM nba_users AS u
WHERE u.Status = 'Enable' 
ORDER BY TotalPoints desc;

如果您需要所有三个值，可以使用子查询或重复计算：

SELECT u.*, (BonusPoints + ResultPoints) as TotalPoints
FROM (SELECT u.*,
             (SELECT SUM(ub.Points) FROM nba_user_bonus ub  WHERE ub.UserId = u.Id) as BonusPoints,
             (SELECT SUM(ur.Points) FROM nba_user_result ur WHERE ur.UserId = u.Id) as ResultPoints
      FROM nba_users AS u
      WHERE u.Status = 'Enable' 
     ) u
ORDER BY TotalPoints desc;

您也可以将此短语称为与group bys的连接。但是，select中包含子查询的方法可能比该方法更快。

编辑：

要在第一种情况下处理NULL，请使用ifnull()或coalesce()：

SELECT u.*,
       (coalesce((SELECT SUM(ub.Points) FROM nba_user_bonus ub  WHERE ub.UserId = u.Id), 0) + 
        coalesce((SELECT SUM(ur.Points) FROM nba_user_result ur WHERE ur.UserId = u.Id), 0)
       ) as TotalPoints
FROM nba_users AS u
WHERE u.Status = 'Enable' 
ORDER BY TotalPoints desc;

Answer 2

不要在语句的SELECT部分中进行子查询，而是使用连接。然后在末尾添加GROUP BY，以便获得不同的U.ID和UR和UB总计。

SELECT 
    u.ID,
    SUM(ub.Points)+     SUM(ur.Points) as TotalPoints
FROM 
    nba_users AS u
    LEFT OUTER JOIN nba_user_bonus as ub on
        u.ID = ub.userid
    LEFT OUTER JOIN nba_user_result as ur on
        u.ID = ur.userid

WHERE u.STATUS = 'Enable'
GROUP BY 1
ORDER BY u.Id ASC

如何获得两个别名表的总和导致mysql的主要结果？

QUERY

2 个答案: