Age Calculation Flaw?

[Poida3934]

I am trying to calculate the age of pre-school students at start of school
year, and have
a "flaw" somewhere if the birth month is the same as start of year month.
The first formula
below gives me the years, the second the months, can anyone spot the
error???

=DateDiff("yyyy",[StudDOB],[Year_Start])+Int(Format([Year_Start],"mmdd")<Format([StudDOB],"mmdd"))

=DateDiff("m",[StudDOB],[Year_Start]) mod 12

So, a student whose birth date is 4th January 2003, and school year start is
1st January
2008, I get 4 years and 0 months as his age (should probably show 11 months,
hehehe).
Any clues folks? Thanks in anticipation, your help in here has been
tremendous over the last
few weeks.

Poida

 

[Albert D. Kallal]

Actually, both your examples don't include the day of the month.

You *need* to include the day of the month for this to work.

So, a student whose birth date is 4th January 2003, and school year start
is

1st January
2008, I get 4 years and 0 months as his age (should probably show 11 months,
hehehe).

Using the code example below, I get
? ageyear(#01/03/2003#,#01/01/2008#)
4

True, the person does not turn 5 untill the 3rd of jan

and, the months is
? agemonths(#01/04/2003#,#01/01/2008#)
11

If the school year starts on the 15th, then the birthday WILL have occurred.

? ageyear(#01/04/2003#,#01/15/2008#)
5

? agemonths(#01/04/2003#,#01/15/2008#)
0


Here is the code:

Public Function AgeYear(dtStart As Date, dtend As Date) As Integer

Dim intYear As Integer

intYear = DateDiff("yyyy", dtStart, dtend)

' if month of this year has not yet past, then
' birthday not yet occured subtrack 1 year

If Month(dtStart) > Month(dtend) Then
intYear = intYear - 1
Else
If Month(dtStart) = Month(dtend) Then
' same month, if day has not yet
' passed, then birthday not yet
If Day(dtStart) > Day(dtend) Then
intYear = intYear - 1
End If
End If
End If

AgeYear = intYear

End Function


Public Function AgeMonths(dtStart As Date, dtend As Date) As Integer

Dim intMonths As Integer

intMonths = DateDiff("m", dtStart, dtend)

' if month of this year has not yet past, then
' birthday not yet occured subtrack 1 year

If Month(dtStart) > Month(dtend) Then
intMonths = intMonths - 1
Else
If Month(dtStart) = Month(dtend) Then
' same month, if day has not yet
' passed, then birthday not yet
If Day(dtStart) > Day(dtend) Then
intMonths = intMonths - 1
End If
End If
End If

AgeMonths = intMonths Mod 12

End Function