Crystal Report NextIsNull({FieldofDetailsA})

[gir...@cdactvm.in]

sir
I need clarification as below

In Crystal Report function, NextIsNull({FieldofDetailsA})
How can we specify the FieldofDetailsA if the fields are taken through
a Stored Procedure say 'rptPurchaseOrder' and in the report design
page the field name is displaying as
'rptPurchaseOrder;1.ProductName'
Is the function can be written as below

NextIsNull({rptPurchaseOrder;1.ProductName})

or to be written as below

NextIsNull({Products.Productname}) where Products is the table.