DELIMITER $$

CREATE FUNCTION ufn_count_employees_by_town(town_name VARCHAR(255))

RETURNS INT DETERMINISTIC 

BEGIN

    DECLARE employee_count INT;

    SELECT COUNT(*) INTO employee_count 

    FROM employees AS e

    JOIN addresses AS a ON e.address_id = a.address_id

    JOIN towns AS t ON t.town_id = a.town_id

    WHERE t.name = town_name;

    RETURN employee_count;

END $$

DELIMITER ;