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"I learned that if you are not doing math with a number then it should be stored as character data."
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The man was in a wrong school :hehe:
There are examples where numbers have nothing to do with math, but they still better to be stored as numbers.
What about numeric sequences? You are no going to apply math to it, as they are mainly for order.
Integers, in this case will take less space and perform much better in ORDER BY then characters, not saying that the order for numbers saved as character datatype will be very different to order based on the numeric value...
I would say if the number you store is a number then use numeric datatype.
If a number is in reality sequence of digits, which very often is subject of some formatting (eg. phone numbers), - then you better to use character datatype. It has nothing to do with math.
There is a blog about choosing wrong ones: http://sqlblog.com/blogs/aaron_bertrand/archive/2009/10/12/bad-habits-to-kick-using-the-wrong-data-type.aspx