Integer vs String in database

Question

When defining datatypes in a database, I have always had a problem with choosing whether to use integers or strings to store certain \'numerical\' data.

Say I am bui

Answer 1

Is '0000' a postcode ? Is it distinct from '0' ?

If it's always a four-digit number, I would always store it as 4 digits, and that would point to keeping it as a string.