Postgres 15

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
 CREATE TABLE IF NOT EXISTS public."distance"
(
     
   fromname TEXT COLLATE pg_catalog."default",
    toname TEXT COLLATE pg_catalog."default",
     distancemiles float,
     diskm  float 
)

CREATE TABLE


CREATE OR REPLACE FUNCTION calculate_distance(lat1 float, lon1 float, lat2 float, lon2 float, units varchar)
RETURNS SETOF "distance" AS $$
    DECLARE
        dist float = 0;
  distkm float = 0;
  distMiles float = 0;
        radlat1 float;
        radlat2 float;
        theta float;
        radtheta float;
    BEGIN
        IF lat1 = lat2 AND lon1 = lon2
            THEN RETURN QUERY SELECT 'userA','userlastA',distMiles,distkm ;
        ELSE
            radlat1 = pi() * lat1 / 180;
            radlat2 = pi() * lat2 / 180;
            theta = lon1 - lon2;
            radtheta = pi() * theta / 180;
            dist = sin(radlat1) * sin(radlat2) + cos(radlat1) * cos(radlat2) * cos(radtheta);

            IF dist > 1 THEN dist = 1; END IF;

            dist = acos(dist);
            dist = dist * 180 / pi();
            dist = dist * 60 * 1.1515;

            IF units = 'K' THEN distkm = dist * 1.609344; END IF;
            IF units = 'M' THEN distMiles = dist * 0.8684; END IF;

            RETURN QUERY SELECT 'userA','userlastA' ,distMiles,distkm  ;
        END IF;
    END;
$$ LANGUAGE plpgsql;

CREATE FUNCTION


SELECT * FROM  calculate_distance(13.08, 80.27, 12.29, 76.63, 'M');
SELECT * FROM calculate_distance(13.08, 80.27, 12.29, 76.63, 'K');


fromname
toname
distancemiles
diskm


userA
userlastA
218.26626129516504
0



SELECT 1




fromname
toname
distancemiles
diskm


userA
userlastA
0
404.49734916836263



SELECT 1