IsNull

[Drus]

What is the "IsNull" used for?

Thanks,
Andrew Andrew Hagenbach
OPUS SYSTEMS, INC.
916.503.3173
ahagenbach@opus-sys.com

 

[butkus]

It is a test for Null values contained in your data source. If the test is true, you can have your formula assign an empty string, or anything for that matter, to a variable to be used later - or produce a string of text directly.

It is useful when trying to extract and report many data elements when not all are required.

My experience has taught me that when Null values exist in a particuler row of data, that you may or may not receive the results you seek unless you do something with Null values first.

My $.02

James Carruth
Network Administrator

 

[dgillz]

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

 

[Sose]

I am trying to get a report to display only records where the elapsed time field is null..

Any suggestions?

 

[rogar]

In the record selection formula:
IsNull({Table.ElapsedTime})