Date Syntax not working

[Huddle]

If the district = D1 and the Date Resolve is null then I want it to count the records. If I take out the date resolve part of the equation it works so there's something wrong in my syntax there. Can you help point it out?

=Sum(IIf([District]="D1",IIf([Date_Resolved]="",1,0)))

[RuralGuy]

How about IIF(IsNull([Date_Resolved]),1,0)?

[Huddle]

That work but then how do I show the once that are closed since I there isn't a "IsNotNull" expression?

[RuralGuy]

That would be expressed as: IIF(Not IsNull([Date_Resolved])

[Huddle]

Great Thanks