Query Problem

Hi.

I have this query:

$querystr = "
    SELECT $wpdb->posts.*
    FROM $wpdb->posts, $wpdb->top, $wpdb->term_relationships
   	WHERE $wpdb->posts.ID = $wpdb->top.post_id
    AND $wpdb->top.DIA_FINAL >= NOW()
    AND $wpdb->top.ESTADO = 'OK'
	AND $wpdb->posts.ID = $wpdb->term_relationships.object_id
	AND $wpdb->term_relationships.term_taxonomy_id = (8,33)
	ORDER BY RAND()
	LIMIT 50
	 ";

The query works, but not fine:

I want resolve all post for term_taxonomy_id = 8 and inside all post of category 8, all of category 33. I want not all post of each category.

Any idea?

thanks