The query must be something like:
Code:
SELECT
MemberID,
Forename,
LastName,
SomeFunction(BirthDate, Date) AS ContactAge,
Iif(Nz(BirthDate,)=0,Null,Chose(Iif(SomeFunction(BirthDate, Date) < 10,1,0)+Iif(SomeFunction(BirthDate, Date) < 13,1,0)+Iif(SomeFunction(BirthDate, Date) BETWEEN 13 AND 15,1,0)+Iif(SomeFunction(BirthDate, Date) BETWEEN 16 AND 18,1,0)+Iif(SomeFunction(BirthDate, Date) BETWEEN 19 AND24,1,0)+Iif(SomeFunction(BirthDate, Date) > 24,1,0),"peewee","younger cadette","older cadet","junior","young man", "old man")) AS AgeGroup
FROM YourTable
Edit: I corrected right query to wrong one immediately after posting it! The right one is
Code:
SELECT
MemberID,
Forename,
LastName,
SomeFunction(BirthDate, Date) AS ContactAge,
Iif(Nz(BirthDate,)=0,Null,Chose(Iif(SomeFunction(BirthDate, Date) > 0,1,0)+Iif(SomeFunction(BirthDate, Date) > 8,1,0)+Iif(SomeFunction(BirthDate, Date) > 12,1,0)+Iif(SomeFunction(BirthDate, Date) > 15,1,0)+Iif(SomeFunction(BirthDate, Date) > 18,1,0)+Iif(SomeFunction(BirthDate, Date) > 24,1,0),"peewee","younger cadette","older cadet","junior","young man", "old man")) AS AgeGroup
FROM YourTable