1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') GROUP BY categories_id' at line 1

SELECT count(*) AS number_in_category, categories_id FROM scot_b2b__products p, scot_b2b__products_to_categories p2c WHERE p.products_id = p2c.products_id AND p.products_fsk_18_hidden = '0' AND p.products_status = '1' AND p2c.categories_id IN () GROUP BY categories_id