sql_mode="oracle" errors on create procedure AS

CREATE PROCEDURE remove_emp (employee_id NUMBER) AS tot_emps NUMBER;

   BEGIN

      DELETE FROM employees

      WHERE employees.employee_id = remove_emp.employee_id;

   tot_emps := tot_emps - 1;

   END;

/

MariaDB [test]> CREATE PROCEDURE remove_emp (employee_id NUMBER) AS tot_emps NUMBER;

ERROR 1064 (42000): 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