how to search for records close to a zip code?

[sneakyimp]

hey everybody:

i'm currently writing some code for a dating website. they want the user to be able to search all the dating profiles for matches that are close to their own zip code. I'm using MYSQL.

I was hoping to be fairly exacting when doing this search:
within 5 miles
within 10 miles
* within 100 miles

etc. but I don't really know how...I would imagine that to be that precise, one would need a GIGANTIC database that maps the distance between any two zip codes in the US...if all 100,000 are cross referenced, don't you get like 99,999 records?

I know that adjacent zip codes have similar numbers but I'm not sure just how close they might be, etc. If anyone can recommend a general heuristic rule about geographic proximity vs. numeric proximity that would be great. some SQL would be great as well as my sql skills are not stellar when it comes to inexact matching or comparison queries.

thnx!

[Mordecai]

The search feature is your friend.
Click here for a nearly identical post...and search to find many more.

[sneakyimp]

Thanks Mordecai! That was fast. I'm checking out that other post...looks like a thorny problem.

[CrashRoX]

You can purchase a zipcode database for a few bucks. I think I we paid 25 for the one we used on a similar. Then with a function you can easily find, you will be able to compare long, and lat lines to get the distance between zipcodes. Searching is a bit more tricky :p