Only return posts that are assigned to both categories

The code below is part of a bigger query that by itself works fine.

But let’s say you have three posts.

1. post a is assigned to category a
2. post b is assigned to category b
3. post c is assigned to category a and b.

What happens now if you select category a and b is that it returns all three posts. But I want it to only return post c, which the code below doesn’t do.

INNER JOIN $wpdb->term_relationships AS term_rel ON posts.ID = term_rel.object_id
INNER JOIN $wpdb->term_taxonomy AS term_tax ON term_rel.term_taxonomy_id = term_tax.term_taxonomy_id
AND term_tax.taxonomy = 'store_category'
AND term_tax.term_id IN (" . implode( ',', $filter_ids ) . ")

Instead of using IN I tried to do this, but that returns no results at all.

AND term_tax.term_id = category a id
AND term_tax.term_id = category b id

Anyone who can point me in the right direction so that it only returns results that have all categories assigned to them?