temporary columns

I'm trying to create a query that will select all the columns in my table and add a temporary one based on a calculation with the data in another column. If it's possible I assume it's using the JOIN and AS parts of a SELECT query, but i keep getting syntax errors or something. Any help is appreciated.

thanks
rick

Your comment is a little confusing, but could you mean something like this?


select column1,column2,column1+column2 as total from tableName;