SELECT *,
111.111 *
    DEGREES(ACOS(LEAST(1.0, COS(RADIANS(Latitude))
         * COS(RADIANS())
         * COS(RADIANS(Longitude - ))
         + SIN(RADIANS(Latitude))
         * SIN(RADIANS())))) AS distance_in_km
 FROM dentists WHERE Type='Promo' AND Status='Live' ORDER BY distance_in_km ASC