Can't execute query

SELECT p.*,c.id as cid FROM products_tw as p, categories_tw c, products_category_tw as it WHERE (p.id = '51781769' || p.serial_no = '51781769') AND p.id = it.pid AND it.category=c.id AND (p.available='1' OR (p.available='2' and p.sdate <= '2018-09-21' AND p.edate >= '2018-09-21')) AND c.available = '1' AND it.category in (������-������) GROUP by it.pid

MySQL Error: Unknown column '������' in 'where clause'

This script cannot continue, terminating.