On Fri, 29 Feb 2008 19:59:20 +0000, Thomas Dalton wrote:
How important are intersections for non-existent categories? Without we could have something like (page_id int, cat_intersect bigint) or (page_id int, cat1 int, cat2 int) to get two cat intersection without collisions; and maybe even scale up by defining n-intersections recursively, without collisions.
How fast are ANDs in SELECT WHEREs? I would guess it's quicker to search by hash than by 2 ints.
I'm not sure, which is why suggested the version that concatenates them into a big int. That may be faster than keeping to indices to and.