Happy New Year, Henry.
You don't need to (and usually must not) reference the field itself; your calculation already reads (implicitly)
so you just need
If ( type = "Compte a Compte" ; amount * -1 ; 0 )
I think I must have had too much of the Xmas wine. Thanks
Good evening and a Happy New Year to you all. This is my first post here!
We're glad to have you hear and hope you find the Discussions useful. Hopefully you'll feel free to post more and ask questions and give feedback to other users too!