How to take the Average of a DATEDIFF column with NULL values?

Question

I am building an SSRS report that can display the average of a calculated datediff column in dd/hh/mm format with the following formula:
=Avg(IIF(Fields!LastCorrectedDate.Value is nothing,0, DATEDIFF("n",cdate(Fields!LastCorrectedDate.Value),cdate(Fields!
LastSignDate.Value)) \(60*24) & ":" & DATEDIFF("n",cdate(Fields!LastCorrectedDate.Value),cdate(Fields!
LastSignDate.Value)) mod (60*24)\60  & ":" & DATEDIFF("n",cdate(Fields!LastCorrectedDate.Value),cdate(Fields!
LastSignDate.Value)) mod (60*24) - (((DATEDIFF("n",cdate(Fields!LastCorrectedDate.Value),cdate(Fields!
LastSignDate.Value)) mod (60*24))\60)*60) ))
SSRS does not raise any errors with the formula and I have used the same formula for other columns without issue. I have noticed that this column includes null values which I think may be the problem. When the reports runs, it returns #ERROR on the column
but does not give a reason why.  I am using SSRS report builder with visual basic logic as opposed to embedding SQL. Any help or feedback would be greatly appreciated.

Answer 1

Hi No Ragrets,
According to your description, you want to calculate the average for the date time difference. Right?
In Reporting Services, Avg() function is only available for numeric values. In this scenario, the DateDiff() function to calculate the minutes difference will return a number. So we can do average calculation based on the return values first. Then we format
it as a time. We have tested this case in our local environment. Please try the following expression:
=floor(avg(DateDiff("n",Fields!StartDate.Value,Fields!EndDate.Value))) \(24*60) &":"&
floor(avg(DateDiff("n",Fields!StartDate.Value,Fields!EndDate.Value))/60 mod 24 )&":"&
floor(avg(DateDiff("n",Fields!StartDate.Value,Fields!EndDate.Value))) mod 60
The result looks like below:
If you have any question, please feel free to ask.
Best Regards,
Simon Hou