根据坐标计算距离（mysql函数）

CREATE DEFINER=`root`@`localhost` FUNCTION `getDistance`(lng1 float, lat1 float, lng2 float, lat2 float) RETURNS int()
BEGIN
DECLARE result double;

DECLARE radLng1 double;
DECLARE radLat1 double;

DECLARE radLng2 double;
DECLARE radLat2 double;

set radLng1 = lng1 * pi() / 180.0;
set radLat1 = lat1 * pi() / 180.0;

set radLng2 = lng2 * pi() / 180.0;
set radLat2 = lat2 * pi() / 180.0;

set result =  * asin(sqrt(pow(sin((radLat1 - radLat2) / ), ) + cos(radLat1) * cos(radLat2) * pow(sin((radLng1 - radLng2) / ), )));
set result = result * 6378.137;
set result = round(result * ) / ;
RETURN result;
END