Dsum return wrong answer

[mikichi]

hi,
i try to create a bank operations system, i have a table with this columns: nameBank, credit, duty, balance
i want to sum all credit and reduce from duty to get the balance like in bottom/
i try with Dsum function like that:

Me.balance = Dsum([credit],"bankigOperations",Me.bankName = [bankName])-Dsum(....)

i dont know why but the first Dsum return to me wrong answer
help plz!
miki

bankName	duty	credit	balance
bank1	3		-3
bank2		2	2
bank1		4	1

[June7]

Should not save balance in table. This should be calculated in aggregate query or on report when needed.

Textbox in report has a RunningSum property which can easily do this.

[mikichi]

thank you,
i read about runningsum and listening to your advice.
i success to sum one column with running sum, but i dont success to reduce one column form other.
thank you!!
miki

[June7]

Arithmetic with null returns null. Need to handle null values.

Try:

=Nz([credit],0)-Nz([duty],0)

[mikichi]

thank you!!