Here is a practical application of the IsNull() function that I just wrote a report for last week. Lets say I have an Item master file, and a Product Structure file. I want a report of purchased items not assigned to a porduct structure, aka "orphaned" items.
I link the Product Structure table to the Item table by Component Item number, then I drag the following fields oon the details section:
{ItemMaster.ItemNo} {ProdStructure.ParentItem}
This gives me every item in the item master file, plus every parent it is used in. So I need to write a record selection formula:
{ItemMaster.PurchorMfgFlag}="P" and
IsNull({ProdStructure.ParentItem})
The "P" gives me puchased items and the Null Parent Item means that the Item No is found no where in the Product Structure file.
Let me know if you have any questions. Software Support for Macola, Crystal Reports and Goldmine
dgilsdorf@mchsi.com