DATEDIF formula with multiple criteria (IF ...)

[Test_Database_2021]

Hi everyone,

So in Excel 2010, I have a DATEDIF formula that works perfectly, which is:
=IF((AND(Y:Y<>"",B:B<>"")),DATEDIF([@[Date of inclusion]],[@[Date of discharge]],"d")/7,""),IF((AND(B:B<>"",Y:Y=""))

B shows the first date (date of inclusion)
Y shows the second date (date of discharge)

What I now want to do is to add a condition where when there is no second date (column Y is empty), the date difference is calculated according to a fixed date (31/12/2020).

So something like this:
=IF((AND(Y:Y<>"",B:B<>"")),DATEDIF([@[Date of inclusion]],[@[Date of discharge]],"d")/7,""),IF((AND(B:B<>"",Y:Y="")),DATEDIF(Y:Y,12/31/2020,"d"/7,""))

...but clearly, this doesn't work as you can't have two DATEDIF formulas with a "false = """ condition in the same cell.

Any ideas? Thanks!

 

[Fluff]

Maybe

=IF([@[Date of inclusion]]<>"",DATEDIF([@[Date of inclusion]],if([@[Date of discharge]]<>"",[@[Date of discharge]],DATE(2020,12,31)),"d")/7,""),"")

 

[Test_Database_2021]

Thanks, but this gives me an error code. It marks the last "" as the error.

 

[Fluff]

Oops, just remove the last ,"") form the formula