حاولت تطبيقها و لكن لم استطع لذلك إستشرت اساتذتى هنا
Consume Amount= IIf([issue date]<#01/08/2016#;consumD0817([consum]))
Consume Amount= IIf([issue date] Between #01/08/2016# And #30/07/2017#;consumA0817([consum]))
Consume Amount=IIf([issue date] Between #01/08/2017# And #30/07/2018#;consumB0817([consum]))
Consume Amount=IIf([issue date] Between #01/08/2018# And #30/07/2019#;consumC0817([consum]))