please give the importance of smart field ,i learned that smart fields are data items some thing related to Business function .but i'm not getting the clear idea.
I don't know how "important" Smartfields are, but they are
typically used in financial reports.
In a few words, it's a BSFN that returns a numeric value,
which can be displayed in your report as if it were an
elementary data item (like a field or a constant).