Question

这就是我所做的，在图像中结果现在我想通过UserSend得到所有组的总和，例如你可以看到maorsapo@gmail.com 在第二个中有7个和3个我想要的不是这个它将是maorsapo@gmail.com，10（7 + 3）我怎么能这样做？

SELECT m.UserSend, Count(*) AS Expr1
FROM Messages AS m
GROUP BY m.UserSend;
union
SELECT F.UserRequest, Count(*) AS Expr1
FROM FavoritesList AS F
GROUP BY F.UserRequest;

https://ibb.co/cbuKrJ

Answer 1

您可以尝试使用结果表的总和

select t.my_user, sum(Expr1)
from (
    SELECT m.UserSend as  my_user, Count(*) AS Expr1
    FROM Messages AS m
    GROUP BY m.UserSend;
    union
    SELECT F.UserRequest, Count(*) AS Expr1
    FROM FavoritesList AS F
    GROUP BY F.UserRequest;
) t 
group by t.my_user

Answer 2

您需要union all而不是union：

SELECT user, sum(cnt)
FROM (SELECT m.UserSend as user, Count(*) AS cnt
      FROM Messages AS m
      GROUP BY m.UserSend;
      UNION ALL
      SELECT F.UserRequest, Count(*) AS cnt
      FROM FavoritesList AS F
      GROUP BY F.UserRequest
     ) as u
GROUP BY user;

UNION将删除重复项，您不想这样做。

我记得MS Access的某些旧版本需要一个视图才能完成此操作，因为子查询中不允许使用union / union all。但这应该没问题。

Answer 3

非常感谢你 SELECT用户，总和（cnt） FROM（选择m.UserSend作为用户，Count（）AS cnt 来自消息AS m GROUP BY m.UserSend; UNION ALL SELECT F.UserRequest，Count（）AS cnt FROM FavoritesList AS F. GROUP BY F.UserRequest ）作为你 GROUP BY用户;

如何在查询中计算联合的总和

3 个答案: