PostgreSQL - 每个用户的MAX值

Question

我有一张桌子

<button id="btn">btn</div>
<button id="btn2">Disable/Enable</div>

我想为每个用户选择User | Phone | Value Peter | 0 | 1 Peter | 456 | 2 Peter | 456 | 3 Paul | 456 | 7 Paul | 789 | 10 值，而不是低于tresshold

对于tresshold 8，我希望结果是

MAX

我已经尝试了GROUP BY和HAVING，但我得到了

Peter | 456 | 3
Paul | 456 | 7

类似的查询逻辑在MySQL中有效，但我不太确定如何在PostgreSQL中使用GROUP BY。我不想打电话给GROUP BY。

Answer 1

我得到了＆＃34; juergen d＆＃34;解决方案，我想出了这个，它给了我更快的结果

SELECT DISTINCT ON(user) user, phone, value
FROM table
WHERE value < 8
ORDER BY user, value DESC;

Answer 2

select t1.*
from your_table t1
join
(
    select user, max(value) as max_value
    from your_table
    where value < 8
    group by user
) t2 on t1.user = t2.user and t1.value = t2.max_value

Answer 3

或者，您可以使用排名功能：

select * from 
(
select *, RANK() OVER (partition by [user] ORDER BY t.value desc ) as value_rank from test_table as t
where t.value < 8
) as t1
where value_rank = 1