[SQL] Radius of a zip code

[Andy Lewis]

Title: Message

Hello all,

 

I was trying to find all zip codes within a given zip code or radius.

 

I have map points and Latitude and Longitude in my zip table.

 

I remember seeing a post or two referencing this but can't see to find it.

 

I've tried the following with no luck:

 

-- 20 Miles

--select 20 * 360.0 / (7900.0 * atan2(1,1) * 4.0);
select * from zip_code where map_loc @ circle(map_point('dallas','tx','75201'), .290105212724467 ) order by city

 

Anyone that has this experience, can you validate this for correctness?

 

Thanks in advance,

 

Andy