SQL hiba!

#0 f_die(catalog_product_list, select distinct a.*, b.name bname, b.node bnode, b.intro bintro, g.node gnode from premiumshop__product a left join premiumshop__product_variations pv on (pv.product_id=a.id) left join premiumshop__brand b on (b.id=a.brand) left join premiumshop__art_grp_key k on (k.product_id=a.id) left join premiumshop__art_grp g on (g.id=k.art_grp_no) where k.art_grp_no= and a.visible=1 and g.visible=1 , You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'and a.visible=1 and g.visible=1' at line 1) called at [/var/www/vhosts/simo.hu/premiumshop.hu/inc/catalog_product_list.inc.php:249] #1 include(/var/www/vhosts/simo.hu/premiumshop.hu/inc/catalog_product_list.inc.php) called at [/var/www/vhosts/simo.hu/premiumshop.hu/catalog.php:350]
request_uri: /webaruhaz/wellion-etrend-kiegeszitok/, script_filename: /var/www/vhosts/simo.hu/premiumshop.hu/catalog.php, line: 1659, referer:
catalog_product_list
select distinct a.*, b.name bname, b.node bnode, b.intro bintro, g.node gnode from premiumshop__product a left join premiumshop__product_variations pv on (pv.product_id=a.id) left join premiumshop__brand b on (b.id=a.brand) left join premiumshop__art_grp_key k on (k.product_id=a.id) left join premiumshop__art_grp g on (g.id=k.art_grp_no) where k.art_grp_no= and a.visible=1 and g.visible=1
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'and a.visible=1 and g.visible=1' at line 1