NATALINA spletna trgovina za male in velike

Error No: 0 - MySQL error 1064: 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' at line 9
Query:
SELECT count(DISTINCT a.artikli_pk) num_products FROM web_artikli a ,web_user_favorites b WHERE a.artikli_pk = b.artikli_pk AND b.users_pk = AND a.visible = 1
#0 /home/natalina/public_html/app/classes/database.php(1270): MySQLDB->fMyQuery('SELECT count(DI...')
#1 /home/natalina/public_html/app/content/ecommerce/class.ecommerce.content.php(1404): MySQLDB->query('SELECT count(DI...')
#2 /home/natalina/public_html/app/content/ecommerce/class.ecommerce.content.php(438): clEcommerceContent->pPageTypeProducts()
#3 /home/natalina/public_html/app/content/class.content.php(771): clEcommerceContent->pPageContentEcommerce()
#4 /home/natalina/public_html/app/content/index.php(267): clContent->pPageContent()
#5 /home/natalina/public_html/app/content/index_switch.php(43): include('/home/natalina/...')
#6 /home/natalina/public_html/index.php(37): include('/home/natalina/...')
#7 {main}