error in the query:select GROUP_CONCAT(related_id) as related_id FROM msc_product_related WHERE product_id =  GROUP BY product_id<br>PDOException: SQLSTATE[42000]: Syntax error or access violation: 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 'GROUP BY product_id' at line 1 in /home/mschkcom/public_html/includes/mysql.class.php:34
Stack trace:
#0 /home/mschkcom/public_html/includes/mysql.class.php(34): PDO->prepare('select GROUP_CO...')
#1 /home/mschkcom/public_html/project/msc/html/product-details.php(26): mysqlclass->prepare('select GROUP_CO...')
#2 /home/mschkcom/public_html/index.php(19): include_once('/home/mschkcom/...')
#3 {main}