计算地图上两个坐标点之间的实际距离

DELIMITER $$


USE `test2`$$


DROP FUNCTION IF EXISTS `GETDISTANCE`$$


CREATE DEFINER=`root`@`%` FUNCTION `GETDISTANCE`(lat1 DOUBLE, lng1 DOUBLE, lat2 DOUBLE, lng2 DOUBLE) RETURNS DOUBLE
    READS SQL DATA
    DETERMINISTIC
BEGIN
DECLARE RAD DOUBLE;
DECLARE EARTH_RADIUS DOUBLE DEFAULT 6378137;
DECLARE radLat1 DOUBLE;
DECLARE radLat2 DOUBLE;
DECLARE radLng1 DOUBLE;
DECLARE radLng2 DOUBLE;
DECLARE s DOUBLE;
SET RAD = PI() / 180.0;
SET radLat1 = lat1 * RAD;
SET radLat2 = lat2 * RAD;
SET radLng1 = lng1 * RAD;
SET radLng2 = lng2 * RAD;
SET s = ACOS(COS(radLat1)*COS(radLat2)*COS(radLng1-radLng2)+SIN(radLat1)*SIN(radLat2))*EARTH_RADIUS;
SET s = ROUND(s * 10000) / 10000;
RETURN s;
END$$

DELIMITER ;