Not quite, however you can set up a query that returns that information as a column, however no actual column exists.
for instance:
SELECT column1, column2, (column1-column2) as result FROM mytable.
And it will return 3 columns. the last one having the value of the operation of column1 minus column 2
----------------------------------
Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.