Ignoring any functions, if you have a table definition like:
create table foo_addrs (
str_num integer,
str_name varchar(100),
x float,
y float
);
Then a query like the following should do the trick (where x0 and y0 are the variables containing the x-y coordinates of the location you are searching from):
select
sqrt(distance) AS distance,
str_num || ' ' || str_name AS address
from
(select (:x0 - x)^2 + (:y0 - y)^2 as distance, *
from foo_addrs order by distance limit 1) as r
This is all valid for PostgreSQL. I believe PostgreSQL also has a spatial coordinate type designed for this kind of thing.
HTH,
Tom
