Question

I’d like to use GROUP BY multiple columns, I think it’s best to start with an example:

SELECT
    eventsviews.eventId,
    showsActive.showId,
    showsActive.venueId,
    COUNT(*) AS count
FROM eventsviews

INNER JOIN events ON events.eventId = eventsviews.eventId
INNER JOIN showsActive ON showsActive.eventId = eventsviews.eventId

WHERE events.status = 1

GROUP BY showsActive.venueId, showsActive.showId, showsActive.eventId
ORDER BY count DESC
LIMIT 100;

Output:

| *eventId* | *showId* | *venueId* | *count* |
+-----------+----------+-----------+---------+
  [...snip...]
| 95        | 92099    | 9770      | 32      |
| 95        | 105472   | 10702     | 32      |
| 3804      | 41225    | 8165      | 17      |
| 3804      | 41226    | 8165      | 17      |
| 923       | 2866     | 5451      | 14      |
| 923       | 20184    | 5930      | 14      |
  [...snip...]

What I would like instead:

| *eventId* | *showId* | *venueId* | *count* |
+-----------+----------+-----------+---------+
| 95        | 92099    | 9770      | 32      |
| 3804      | 41226    | 8165      | 17      |
| 923       | 20184    | 5930      | 14      |

So, I want my data grouped by eventId, but only once for each showId and venueId …

I actually have a SQL query that does that, but it has 8 subqueries and is as slow as a T-Ford … And since this is executed on every page load, speeding things up looks like a good idea!

There are a few questions like this, and I’ve tried many different things, but I’ve been at this query for an hour and I can’t seem to get it to work as I want 🙁

Thanks!

Answer 1

You probably want either a min or a max on showid, and then not include it in the group by, I can’t tell which because looking at your “prefered” resultset, you have both.