Re: Zip Code Proximity search

[tri.truong]

Here's a code snippet that gives all zip codes within a certain distance of a provided zip code. It probably makes sense to put the formula into a function:

SELECT a.zip_zip AS zip
FROM zip a,
zip b
WHERE (2*3956*ASIN( (SQRT( POWER(SIN(((a.zip_lat_rad-b.zip_lat_rad))/2),2) +
COS(b.zip_lat_rad) * COS(a.zip_lat_rad) *
POWER(SIN(((abs(a.zip_long_rad)-abs(b.zip_long_rad)))/2),2) )) ) )
< 11 -- provide distance+1 here
AND b.zip_zip = '08831'

Hope this helps.

-T