Mysql Datatype for US Zip (Postal Codes)

Question

I am writing a web application, that is US specific, so the format that other countries use for postal codes are not important. I have a list of us zip codes that i am trying to

Answer 1

If he makes it Char(6), then he can handle Canadian postal codes as well.

When you consider that there is a maximum of 100,000 5-digit Zip Code and how little space it would take up even if you made the entire table memory-resident, there's no reason not to.