Thank you for your post.
It may help to better understand your relationships. It sounds like you have "Account::accountnumber" linked to "Bookings::accountnumber_debet", since it is working properly.
In your Relationships graph, click on the bottom left icon to add a new table, and select the Bookings table. You should now have a "Bookings 2" table displayed.
Now, set the relationship so that "Account::accountnumber" is linked to "Bookings 2::accountnumber_credit".
Your "totamount debet" field is working properly, so don't touch that.
Now, create your "totamount_credit" calculation field with the formula:
Sum (Bookings 2::amount)
You will now get the correct result.
If you need clarification for any of the above steps, please let me know.
thanks allready did that so i was on the right track but i created a layout with the table
bookings and that was giving me the wrong results.
I created a new layout with bookings 2 and that gave me the right results.
thanks for your reply it was very helpfull.