SQLite : DELETE on multiple WHERE criteria from query - sqlite

Question

I have a SQLite database where I need to delete records from a many-to-many table, based on query results where 2 criteria for each row must be met.
As an example, take 2 tables :
oldEvents <select_query>
user_id | event_id qry_user_id | qry_event_id
---------+---------- -------------+-------------
1 | aaa 2 | aaa
2 | aaa 3 | bbb
2 | bbb 1 | ccc
3 | bbb
1 | ccc
3 | ccc
From table oldEvents, I want to delete each row that appears in the query, so as to end up with:
oldEvents
user_id | event_id
---------+----------
1 | aaa
2 | bbb
3 | ccc
Until now, I use a cumbersome DELETE query that concatenates the qry_user_id and qry_event_id, and uses them in an EXISTS sub-clause :
DELETE FROM oldEvents
WHERE EXISTS
(
SELECT user_id||event_id AS deleteCombo
FROM oldEvents
WHERE deleteCombo IN
(
SELECT qry_user_id||qry_event_id
FROM
<select_query>
)
)
It works, but is hardly readable, and wouldn't scale once more variables enter the scene.
I can't repeat the select_query inline in an AND-clause, because it is, itsself, a rather complicated query (triple-JOIN).
I could write the query data to a temporary table, but would rather not do that.
Anyone a suggestion on how to write a DELETE that accepts multiple WHERE criteria from a query ?

Answer 1

Enclose your query inside a CTE like this:
WITH cte(user_id, event_id) AS (
<your query here>
)
DELETE FROM oldEvents
WHERE (user_id, event_id) IN (SELECT user_id, event_id FROM cte);
See the demo.
Results:
SELECT * FROM oldEvents;
| user_id | event_id |
| ------- | -------- |
| 1 | aaa |
| 2 | bbb |
| 3 | ccc |