mysql COUNT results with GROUP BY
Your requirement is to get count of number of groups. So we need two operations-
- Group(inner query)
- Count(outer query)
Following query will do precisely that:
SELECT COUNT(*)
FROM
(
SELECT COUNT(id)
FROM my_table
GROUP BY first_linked_table_id,
second_linked_table_id
) t
If you want to count the rows, I think you're going to need a subquery. Something like this:
SELECT COUNT(*) FROM (
SELECT COUNT(id) FROM my_table GROUP BY first_linked_table_id, second_linked_table_id
);