根据经纬度计算距离的公式

private const double EARTH_RADIUS = 6378.137;
private static double rad(double d)
{
   return d * Math.PI / 180.0;
}

public static double GetDistance(double lat1, double lng1, double lat2, double lng2)
{
   double radLat1 = rad(lat1);
   double radLat2 = rad(lat2);
   double a = radLat1 - radLat2;
   double b = rad(lng1) - rad(lng2);

   double 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 * EARTH_RADIUS;
   s = Math.Round(s * 10000) / 10000;
   return s;
}

方便的改成sql语句

假设计算118.041 36.793与数据库内坐标点的距离

mysql> select 6378137*2*asin(Sqrt(power(sin((36.793-domlat)*pi()/360),2) + Cos(36.793*pi()/180)*Cos(domlat*pi()/180)*power(sin((118.041-domlon)*pi()/360),2))) as distance,domip from dominfo order by distance;

精简一下啊

select 12756274*asin(Sqrt(power(sin((36.793-domlat)*0.008726646),2) + Cos(36.793*0.0174533)*Cos(domlat*0.0174533)*power(sin((118.041-domlon)*0.008726646),2))) as distance,domip from dominfo order by distance;