I have a MySQL database table like following:
x
id task_id users
1 1 1
1 2 2
2 1 2
2 2 1
2 10 1
3 1 2
3 2 2
3 3 2
4 1 2
I want to select id’s who have multiple users. In this condition users 1 and 2 are valid. But the problem is, along with above condition I also wanted to select those who do not have a task_id = 10. So final output should be id = 1.
I achieved first condition fulfilled by the help of this post.
But could not achieved result excluding task_id = 10 because trying with following query, it is still showing both users 1 and 2.
select distinct t.id
from table as t
join (
select id
from table
group by id
having count(distinct users) > 1
) as t2
on t.id = t2.id
AND task_id != 10
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Answer
Just use aggregation and having
;
select id
from t
group by t
having count(distinct user) > 1 and
sum(task_id = 10) = 0;
If you wanted the original rows, I would express this using exists
:
select t.*
from t
where not exists (select 1 from t t2 where t2.id = t.id and t2.task_id = 10) and
exists (select 1 from t t2 where t2.id = t.id and t2.user <> t.user);