Pad a string with leading zeros so it's 3 characters long in SQL Server 2008

Question

I have a string that is up to 3 characters long when it\'s first created in SQL Server 2008 R2.

I would like to pad it with leading zeros, so if its original value w

Answer 1

If the field is already a string, this will work

 SELECT RIGHT('000'+ISNULL(field,''),3)

If you want nulls to show as '000'

It might be an integer -- then you would want

 SELECT RIGHT('000'+CAST(field AS VARCHAR(3)),3)

As required by the question this answer only works if the length <= 3, if you want something larger you need to change the string constant and the two integer constants to the width needed. eg '0000' and VARCHAR(4)),4