Error while processing the request: (MySQL server has gone away)
SELECT `order_number`.`rang` FROM 
		(SELECT 
				`all_institutions`.`id`,
				@num:=@num+1 as `rang`
			FROM `institutions` AS `all_institutions`, (SELECT @num := 0) as `t`
			WHERE `all_institutions`.`region`='21'
				AND `all_institutions`.`type`='school'
			GROUP BY `all_institutions`.`id` ASC
			ORDER BY `all_institutions`.`id` ASC, `all_institutions`.`rating` DESC
		) AS `order_number`
	WHERE `order_number`.`id`='20096'