mysql 函数
DROP FUNCTION IF EXISTS func_calcDistance；
CREATE FUNCTION func_calcDistance(
origLng DECIMAL(20,6),
origLat DECIMAL(20,6),
longitude DECIMAL(20,6),
latitude DECIMAL(20,6)
)
RETURNS DOUBLE
BEGIN
DECLARE result DOUBLE DEFAULT 0;
SET result = round(6378.138*2*asin(
sqrt(pow(sin((origLat*pi()/180-latitude*pi()/180)/2),2)+
cos(origLat*pi()/180)*cos(latitude*pi()/180)*pow(sin((origLng*pi()/180-longitude*pi()/180)/2),2)))*1000);
RETURN result;
END;
IN RUBY MIGRATION
ActiveRecord::Base.connection.execute <<-
SQL
DROP FUNCTION IF EXISTS func_calcDistance；
CREATE FUNCTION func_calcDistance(
origLng
DECIMAL(
20,
6),
origLat
DECIMAL(
20,
6),
longitude
DECIMAL(
20,
6),
latitude
DECIMAL(
20,
6)
)
RETURNS DOUBLE
BEGIN
DECLARE result
DOUBLE DEFAULT 0;
SET result = round(
6378.138*
2*asin(
sqrt(pow(sin((origLat*pi()/
180-latitude*pi()/
180)/
2),
2)+cos(origLat*pi()/
180)*cos(latitude*pi()/
180)*pow(sin((origLng*pi()/
180-longitude*pi()/
180)/
2),
2)))*
1000);
RETURN result;
END
SQL
LastestDeviceLocation.select(
"func_calcDistance() as distance").order(
"distance")
