Question

First of all, here’s the query I will talk about :

SELECT route_id, direction_id
FROM stop_times
LEFT JOIN trips USING (trip_id)
WHERE stop_id= 1002
GROUP BY CONCAT(route_id, direction_id)

Example of the expected results :

route_id    |   direction_id
-----------------------------
106         |   0
106         |   1
13          |   0
13          |   1
21          |   0
4           |   0
4           |   1
6           |   0

So, running this query will take an averge of 0.088 second. This is ok… But if I remove the GROUP BY it take 0.0026 second.

Now my question is :

Will it be better to do the GROUP BY and handle everything in MySQL or fetch everything and handle it in an array in PHP ?

Thanks

Answer 1

You can replace this:

GROUP BY CONCAT(route_id, direction_id)

by this:

GROUP BY route_id, direction_id

You will have the same results in much less time.