Converting Data Type of a full Column/Field I have a primary key ID column I want  to convert to a string, any type of string.
Now, I know how to do this for a specific value, by using either CAST or CONVERT. But how do I go about doing it for the whole field? I guess we use some type of Transact SQL , but I would appreciate some pointers on how to do this.
Thanks.
I'm not sure what you mean by 'whole field", but this is how you'd convert an Integer to a varchar string.  The 'second' select proves it's a string because you can concatenate brackets around it.

You'd apply the same technique when selecting rows from a table.

DECLARE @IntColumn int = 5
select convert(varchar(20),@IntColumn)
select '[' + convert(varchar(20),@IntColumn) + ']'