replace a null date with a date in the same record

[gmpdba]

Hey all -

I don't if this is simple or not.  I am trying to calculate days between the two dates in the same record.  Some dates in the first column are null and DATEDIFF does not like this.  I would like to replace the second date with the first if the first is null.  

If somebody could give me some direction, that would be awesome.

Thanks,

Mike 

[Greg_Deckler]

Something like this?

Days = IF(ISBLANK([Date]),DATEDIFF([EndDate],[EndDate],DAY),DATEDIFF([Date],[EndDate],DAY))

[gmpdba]

Thank you - I have got to tinker with formula but will get back with this post next week.