如何将语句按其user_id分组,我不断获得已经在user_id上使用分组依据的2和3重复项?似乎是什么错误?
SELECT user_id, SUM(amount)
FROM users INNER JOIN
user_privileges
ON users.id = user_privileges.user_id
GROUP BY user_id, amount
ORDER BY user_id;
+---------+-------------+
| user_id | SUM(amount) |
+---------+-------------+
| 1 | 3000.00 |
| 2 | 2500.00 |
| 2 | 19000.00 |
| 3 | 2500.00 |
| 3 | 19000.00 |
| 4 | 12000.00 |
+---------+-------------+
简单的答案是简单地按分组userid
,而不是amount
:
SELECT user_id, SUM(amount)
FROM users INNER JOIN
user_privileges
ON users.id = user_privileges.user_id
GROUP BY user_id
ORDER BY user_id;
但是,join
似乎甚至没有必要。您可以这样做:
SELECT user_id, SUM(amount)
FROM user_privileges
GROUP BY user_id
ORDER BY user_id;
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