Trying to calculate Days between 2 date columns. Both Columns have nulls or no values

[ResearchDev]

There is Actual Start and Actual End Date. Both columns have null values as project is in progress or no given date. Keep getting errors on below. Any suggestions? Just trying to get a number value on the difference between these 2 columns. Thanks

Days Between = If('BI Projects'[Actual Start]=BLANK(),"",DATEDIFF('BI Projects'[Actual Start], 'BI Projects'[Actual End],DAY))

[ResearchDev]

Thanks so much! Worked like magic!

[tamerj1 · Accepted solution]

Hi @ResearchDev 
PLease try

Days Between =
IF (
    'BI Projects'[Actual Start] <> BLANK ()
        && 'BI Projects'[Actual End] <> BLANK (),
    DATEDIFF ( 'BI Projects'[Actual Start], 'BI Projects'[Actual End], DAY )
)

[ResearchDev]

Thanks so much!