I want to add a bit column that is not in the database but will be used in the interface something like

select colunm2, [bit] as printid from tblprojects where id > 1

when you say that you want to add it 'on the fly', does that mean that you want to put an extra field into a table and remove it during a routine of some sort? Adding columns to tables 'on the fly' is an interesting idea..

to add a column, try...

ALTER TABLE  tblObjects ADD
       [printid] BIT