sql根据坐标算距离

 CREATE FUNCTION ConvertXYToDistance(@la1 DECIMAL,@lo1 DECIMAL,@la2 DECIMAL,@lo2 DECIMAL)
RETURNS FLOAT
AS
BEGIN
 BEGIN
   RETURN (Round(6378.137*2*Asin(
          Sqrt(
          power(Sin((@la1*PI()/180)-(@la2*PI()/180))/2,2)+
          Cos(@la1*PI()/180)*COS(@la2*PI()/180)*power(SIN((@lo1*PI()/180)-(@lo2*PI()/180))/2,2)
          ))*10000,0)/10000)
 END      
END