Question

Working with MTA API.

stop_times table looks like this:
trip_id, stop_id

trip_id is repeated as stop_ids are listed per row. Example:

  1111, 1
  1111, 2
  1111, 3
  2222, 1
  2222, 3
  3333, 1
  3333, 2

Goal is to select trip_id of a train that we know will definitely stop at two specific stations.
If we want trains that will stop at 1 and 3, we will get trips 1111, and 2222.
Or if 1 and 2, then 1111 and 3333.

Here’s what I wrote quickly, and of course it runs rather slow:

SELECT trip_id 
FROM stop_times 
WHERE stop_id=## 
  AND trip_id IN (SELECT trip_id FROM stop_times WHERE stop_id=##)

Basically, I am trying to do the equivalent of MS SQL INTERSECT.

How can I optimize this to run better?

Answer 1

select trip_id 
from stop_times 
where stop_id in (111, 222)
group by trip_id
having count(distinct stop_id) = 2