1054 - Unknown column 'priority' in 'order clause'

SELECT o.offer_id, o.store ,o.offer_title, o.address, o.offer_desc, o.phone, o.end, o.terms, o.special, o.business_id, o.custom_voucher, b.logo, b.partnership, c.cat_name, o.cat_id, business_gateway.gatename, o.site_name, o.cluster_default_town, o.email_add FROM offers o LEFT JOIN business b ON o.business_id=b.business_id LEFT JOIN business_category c ON o.cat_id=c.cat_id LEFT JOIN business_gateway ON o.business_id=business_gateway.business_id WHERE o.end >= '2018-08-21' AND o.validate ='y' AND ( o.special = '0' OR o.special = '' ) AND o.site_name ='deepsouth' ORDER BY priority DESC, RAND()