Error SQL:

QUERY:
SELECT `id`, `parent` FROM `ctim_ru_cat` WHERE `id` =
MYSQL Error:
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 '' at line 1
stack trace:

#0  sql->query(SELECT `id`, `parent` FROM `ctim_ru_cat` WHERE `id` = ) called at [/var/www/vhosts/adinex.kz/httpdocs/include/classes/db.php:68]
#1  sql->fetch_one(SELECT `id`, `parent` FROM `ctim_ru_cat` WHERE `id` = ) called at [/var/www/vhosts/adinex.kz/httpdocs/include/functions.php:2637]
#2  getCategoryParent() called at [/var/www/vhosts/adinex.kz/httpdocs/include/functions.php:2649]
#3  getCategoriesByParent() called at [/var/www/vhosts/adinex.kz/httpdocs/modules/cat/bcms.php:24]
#4  require_once(/var/www/vhosts/adinex.kz/httpdocs/modules/cat/bcms.php) called at [/var/www/vhosts/adinex.kz/httpdocs/bcms.php:210]