sql:

drop function getDistance;
DELIMITER $$  
CREATE DEFINER=`root`@`localhost` FUNCTION `getDistance`(
     lng1 float(10,7) 
    ,lat1 float(10,7)
    ,lng2 float(10,7) 
    ,lat2 float(10,7)
) RETURNS double
begin
    declare d double;
    declare radius int;
    set radius = 6378140; #假設地球為正球形，直徑為6378140米
    set d = (2*ATAN2(SQRT(SIN((lat1-lat2)*PI()/180/2)   
        *SIN((lat1-lat2)*PI()/180/2)+   
        COS(lat2*PI()/180)*COS(lat1*PI()/180)   
        *SIN((lng1-lng2)*PI()/180/2)   
        *SIN((lng1-lng2)*PI()/180/2)),   
        SQRT(1-SIN((lat1-lat2)*PI()/180/2)   
        *SIN((lat1-lat2)*PI()/180/2)   
        +COS(lat2*PI()/180)*COS(lat1*PI()/180)   
        *SIN((lng1-lng2)*PI()/180/2)   
        *SIN((lng1-lng2)*PI()/180/2))))*radius;
    return d;
end
$$
DELIMITER ;

select getDistance(39.9458190611,116.7906536806,39.9475430611,116.7971416806);
 

JS:

//進行經緯度轉換為距離的計算
function Rad(d){
  return d * Math.PI / 180.0;//經緯度轉換成三角函式中度分表形式。
}

//計算距離 返回米，引數分別為第一點的緯度，經度；第二點的緯度，經度
function GetDistance(lat1,lng1,lat2,lng2){

   var radLat1 = Rad(lat1);
   var radLat2 = Rad(lat2);
   var a = radLat1 - radLat2;
   var  b = Rad(lng1) - Rad(lng2);
   var s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) +
   Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
   s = s *6378.137 ;// EARTH_RADIUS;
   s = Math.round(s * 10000) / 10; //輸出為米
   //s=s.toFixed(4);
   return s;
}