Question

i have DataBase function that calculate distance by coordinates

CREATE OR REPLACE FUNCTION distance(lat1 FLOAT, lon1 FLOAT, lat2 FLOAT, lon2 FLOAT) RETURNS FLOAT AS $$
DECLARE                                                   
    x float = 69.1 * (lat2 - lat1);                           
    y float = 69.1 * (lon2 - lon1) * cos(lat1 / 57.3);        
BEGIN                                                     
    RETURN sqrt(x * x + y * y);                               
END  
$$ LANGUAGE plpgsql;

now i have 2 tables (with one to one relation) one called

person with columns –> Personid, name, lastname

and one

location with columns –> Personid,latitude,longtitude.

now i try to get the person that the distance is less to 5 using the distnace function

i start with this following query to get the id first

select loc.id,loc.latitude,loc.longitude from location loc
where distance(123,456,loc.latitude,loc.longitude)<0.5

but don’t know how to get the all persons with the id from the above query.

how can i do that?
thanks in advance.

Answer 1

Is this what your are looking for?

select p.*, loc.id,loc.latitude,loc.longitude 
from location loc inner join person p on (p.Personid=loc.Personid)
where distance(123,456,loc.latitude,loc.longitude)<0.5