Formulas using conditional "if" , "and", "or" according to dates

[Johnpen21]

Hello,

I'm looking for some help with one formula on the Excel database I'm working on (column Q).

It is about calculating the delay (in # days) between two dates. The problem with making this difference is that only one of them is fixed and the other varies (depending on the date). I

n the attached Excel I had to do it case by case (row by row) for column Q, but I'm looking for a formula to automate it.

Thank you in advance for your help and advice!

John

PS: I also had doubts about my column C and D formulas but they seem to work. Feel free to give me your opinion on them. Thank you!

[#2]

@Johnpen21 

click the link in your sample workbook or go tohttps://exceljet.net/formula/get-days-months-and-years-between-dates#:~:text=To%20calculate%20and%20... 

cheers

[#3]

Here is an example without an error display if there is no date in a cell.
=IF(ISERROR(DATEDIF(B2,A2,"d")),DATEDIF(A2,B2,"d"),DATEDIF(B2,A2,"d"))

I would be happy to know if I could help.

Nikolino
I know I don't know anything (Socrates)