I want to substract those two following selections from my KIT table
and put the result in a new field called DELTAPRICE. Do i need to create
a function to take care of the script ?

select DETAIL_KIT.PRIX_MARGE_DETAIL, DETAIL_KIT.PRINCIPAL from
DETAIL_KIT where PRINCIPAL ='O' order by NO_ORDRE

[ minus ]

select DETAIL_KIT.PRIX_MARGE_DETAIL, DETAIL_KIT.PRINCIPAL from
DETAIL_KIT where PRINCIPAL ='N' order by NO_ORDRE

THANK ..... a lot ...
Richard P