trapping errors - is there access equivalent of iserror in excel

[grapevine]

I have the field shown below in a query which is now working properly and correctly putting either Overdue or Not Overdue in a new field. I am then searching on this field to obtain any overdue records. This is all fine.

Reviewdate1: IIf(DateAdd("d",(([courseplannedenddate]-[coursestartdate])/5),[coursestartdate])<=Date(),"overdue","notoverdue")

But, if either the courseplannedenddate or the coursestartdate are empty then the whole query fails (data mismatch). How can I trap the error in Access. If this was a problem in Excel I would use iserror but I have no idea of the syntax to use in Access.

Can you do a nested if in Access?
How can I trap the error?
Or is there a better way of approaching this? Am I thinking too much Excel and not enough Access?
Any assistance greatly appreciated
Marion

 

[thingssocomplex]

Could you not use 'Is Null' Or 'Is Not Null' in your query on the date fields!

 

[grapevine]

Thank you so much - such a easy solution! I have tested it out and everything works a treat.

Much obliged for your time.
Marion

 

[thingssocomplex]

Hi Marion,

I am still very much a novice myself, but to answer your question you can nest IIF statements just by adding multiple IIF statements and it would check the condition of True Or False on each.

 

[grapevine]

Thank you for your comment about nested ifs. I had experimented but I could not get the iserror part of the if problem sorted so your first solution was so clean and simple that I used that instead.

Many thanks for your help