select rows with condition in other rows - mysql

Question

I want select rows from my table with last status_Id if there is a row with status_Id = 2 for that rows
ticketStatus_Id ticket_Id status_Id
======================================
1 1 1
2 1 2 -
3 1 3 *
4 2 1
5 3 1
6 3 2 - *
7 4 1
8 4 2 -
9 4 3
10 4 4 *
I want select just rows 3, 6, 10. there are another rows with status_Id = 2 (rows 2, 6, 8) for that ticket_Id,
In other word How to select rows 3,6,10 with ticket_Id =1,3,4 that there are another row with these ticket_Ids and status_Id=2 (rows 2,6,8)

Answer 1

If you want the complete row, then I would view this as exists:
select t.*
from t
where exists (select 1
from t t2
where t2.ticket_id = t.ticket_id and t2.status_id = 2
) and
t.status_Id = (select max(t2.status_id)
from t t2
where t2.ticket_id = t.ticket_id
);
If you just want the ticket_id and status_id (and not the whole row), I would recommend aggregation:
select ticket_id, max(status_id)
from t
group by ticket_id
having sum(status_id = 2) > 0;
In your case, ticketStatus_Id seems to increase with status_id, so you can use:
select max(ticketStatus_Id) as ticketStatus_Id, ticket_id, max(status_id) as Status_Id
from t
group by ticket_id
having sum(status_id = 2) > 0;

Answer 2

First, for each ticket we get the row with the highest status. We can do this with a self-join. Each row is joined with the row with the next highest status. We select the rows which have no higher status, those will be the highest. Here's a more detailed explanation.
select ts1.*
from ticket_statuses ts1
left outer join ticket_statuses ts2
on ts1.ticket_Id = ts2.ticket_Id
and ts1.status_Id < ts2.status_Id
where ts2.ticketStatus_Id is null
3 1 3
4 2 1
6 3 2
10 4 4
11 5 3
Note that I've added a curve-ball of 11, 5, 3 to ensure we only select tickets with a status of 2, not greater than 2.
Then we can use that as a CTE (or subquery if you're not using MySQL 8) and select only those tickets who have a status of 2.
with max_statuses as (
select ts1.*
from ticket_statuses ts1
left outer join ticket_statuses ts2
on ts1.ticket_Id = ts2.ticket_Id
and ts1.status_Id < ts2.status_Id
where ts2.ticketStatus_Id is null
)
select ms.*
from max_statuses ms
join ticket_statuses ts
on ms.ticket_id = ts.ticket_id
and ts.status_id = 2;
3 1 3
6 3 2
10 4 4
This approach ensures we select the complete rows with the highest statuses and any extra data they may contain.
dbfiddle

Answer 3

This is basicaly a "last row per group" problem. You will find some solutions here. My prefered solution would be:
select t.*
from (
select max(ticketStatus_Id) as ticketStatus_Id
from mytable
group by ticket_Id
) tmax
join mytable t using(ticketStatus_Id)
The difference in your question is that you have a condition requiring a specific value within the group. This can be solved with a JOIN within the subquery:
select t.*
from (
select max(t1.ticketStatus_Id) as ticketStatus_Id
from mytable t2
join mytable t1 using(ticket_Id)
where t2.status_Id = 2
group by t2.ticket_Id
) tmax
join mytable t using(ticketStatus_Id)
Result:
| ticketStatus_Id | ticket_Id | status_Id |
| --------------- | --------- | --------- |
| 3 | 1 | 3 |
| 6 | 3 | 2 |
| 10 | 4 | 4 |
View on DB Fiddle
A solution using window functions could be:
select ticketStatus_Id, ticket_Id, status_Id
from (
select *
, row_number() over (partition by ticket_Id order by ticketStatus_Id desc) as rn
, bit_or(status_Id = 2) over (partition by ticket_Id) > 0 as has_status2
from mytable
) x
where has_status2 and rn = 1
A quite expressive way is to use EXISTS and NOT EXISTS subquery conditions:
select t.*
from mytable t
where exists (
select *
from mytable t1
where t1.ticket_Id = t.ticket_Id
and t1.status_Id = 2
)
and not exists (
select *
from mytable t1
where t1.ticket_Id = t.ticket_Id
and t1.ticketStatus_Id > t.ticketStatus_Id
)

Answer 4

SELECT a.*
FROM t a
JOIN
(
SELECT ticket_id, MAX(status_id) max_status_id
FROM t
WHERE status_id >= 2
GROUP BY ticket_id
) b
ON a.ticket_id = b.ticket_id
AND a.status_id = b.max_status_id;

Answer 5

SELECT
MAX(m1.ticketstatus_Id) as ticket_status,
m1.ticket_Id as ticket,
MAX(m1.status_Id) as status
FROM mytable m1
WHERE
m1.ticket_Id in (select m2.ticket_Id from mytable m2 where m2.ticket_Id=m1.ticket_Id and m2.status_Id=2)
GROUP BY m1.ticket_Id