MariaDB: Match requests with work performed where total > 0 using a case - datetime

Question

I have a request table and a work table. For request type 1, 2, 4, or 5 I need to sum the work performed of type 6 or 7 where 6 represents effectively +1 and 7 represents -1. Exclude any requests where the request's work sum is <=0 or work were done before the most recent request.
The query details are:
Find requests type in (1, 2, 4, 5) by createDate.
For each request date found, sum work type in (6, 7) as +1 or -1 until the next request createDate.
Output any requests work sum > 0 before the next request.
The sample tables:
create table request
(
Id bigint not null,
userId bigint,
type bigint not null,
creationDate timestamp not null
);
create table work
(
Id bigint not null,
type bigint not null,
creationDate timestamp not null
);
The sample data:
insert into request (Id, userId, type, creationDate)
values (4, 45, 2, '2022-12-12 11:02:17'),
(9, 64, 2, '2022-12-12 01:01:18'),
(2, 92, 2, '2022-12-11 21:36:36'),
(2, 21, 2, '2022-12-11 21:25:54'),
(1, 3, 2, '2022-12-11 21:13:58'),
(7, 243, 2, '2022-12-11 21:04:05'),
(8, 24, 2, '2022-12-11 21:01:23');
insert into work (Id, type, creationDate)
values (3, 7, '2022-12-11 00:00:00'),
(6, 7, '2022-12-11 00:00:00'),
(11, 7, '2022-12-11 00:00:00'),
(6, 7, '2022-12-11 00:00:00'),
(1, 6, '2022-12-11 00:00:00'),
(2, 6, '2022-12-11 00:00:00'),
(11, 7, '2022-12-11 00:00:00'),
(5, 7, '2022-12-11 00:00:00'),
(1, 6, '2022-12-11 00:00:00'),
(11, 7, '2022-12-12 00:00:00'),
(4, 6, '2022-12-12 00:00:00'),
(8, 7, '2022-12-12 00:00:00');
The attempted query:
select id, sum(total), type, creationDate from (
select id, 0 as total, type, creationDate from request
union
select id, case type when 6 then 1 when 7 then -1 end as total, type, creationDate from work
) a where total > 0 group by id
This takes too long on live data, but works on small sets like this fiddle.
There is a challenge in the data, the timestamp for requests includes the time, but the work only has date with no timestamp.
The fiddle reports:
id
sum(total)
type
creationDate
1
1
6
2022-12-11 00:00:00
2
1
6
2022-12-11 00:00:00
4
1
6
2022-12-13 00:00:00
However both 1 and 2 are invalidated because the timestamp of the request is technically greater than the work. The expected output should be:
id
sum(total)
type
creationDate
4
1
6
2022-12-13 00:00:00
For id = 4, the work had the date of 2022-12-13 00:00:00 and the request was timestamped 2022-12-12 11:02:17.

Answer 1

One way to accomplish this is to use a subquery to join the two tables together and then group the results
Here's an example:
SELECT r.Id, SUM(CASE w.type WHEN 6 THEN 1 WHEN 7 THEN -1 END) as total, r.type, r.creationDate
FROM request r
JOIN (
SELECT Id, type, creationDate
FROM work
WHERE type IN (6,7)
) w ON w.creationDate >= r.creationDate
WHERE r.type IN (1,2,4,5)
GROUP BY r.Id, r.type, r.creationDate
HAVING total > 0