Mysql 从两个表中选择值之和,并按公共外键分组
我有两张桌子,我想: 1。-从表“A”中选择每个“id\U用户”的计数: 查询:Mysql 从两个表中选择值之和,并按公共外键分组,mysql,sql,join,Mysql,Sql,Join,我有两张桌子,我想: 1。-从表“A”中选择每个“id\U用户”的计数: 查询: SELECT COUNT(*), user.user_name as user_name FROM A INNER JOIN user ON A.ID_user = user.ID_USER GROUP BY ID_user; SELECT SCORE, user.user_name as user_name FROM B INNER JOIN user ON B.id_user = user.id_user_
SELECT COUNT(*), user.user_name as user_name
FROM A
INNER JOIN user
ON A.ID_user = user.ID_USER
GROUP BY ID_user;
SELECT SCORE, user.user_name as user_name
FROM B
INNER JOIN user
ON B.id_user = user.id_user_name
GROUP BY id_user;
结果:
2.-从表“B”中选择每个“id\U用户”的价值分数
查询:
SELECT COUNT(*), user.user_name as user_name
FROM A
INNER JOIN user
ON A.ID_user = user.ID_USER
GROUP BY ID_user;
SELECT SCORE, user.user_name as user_name
FROM B
INNER JOIN user
ON B.id_user = user.id_user_name
GROUP BY id_user;
结果:
3。-将这两个值相加,并显示按用户名分组的总分:
我的预期输出是这样的,包括表A和表B上的分数总和:
预期产出:
这就是你想要的吗
select u.*,
(select sum(a.score) from a where a.id_user = u.id_user) as a_sum,
(select sum(b.score) from b where b.id_user = u.id_user) as b_sum
from user u;
如果您想要总分,只需将它们相加:
select u.*,
( (select COUNT(1) from a where a.id_user = u.id_user) +
(select coalesce(sum(b.score), 0) from b where b.id_user = u.id_user)
) as ab_sum
from user u;
@克里斯托弗马蒂内兹。如果你想要总数,就把它们加在一起。