DateDiff Function

Syntax
DateDiff(interval, dateexpr1, dateexpr2)
Group
Time/Date
Description
Return the number of intervals between two dates.
Parameters Description
interval This string value indicates which kind of interval to subtract.
dateexpr1 Calculate the interval from this date value to dateexpr2. If this value is Null then Null is returned.
dateexpr2 Calculate the interval from dateexpr1 to this date value. If this value is Null then Null is returned.
Interval Description
yyyy Year
q Quarter
m Month
y Day of year
d Day
w Weekday
ww Week
h Hour
n Minute
s Second
See Also
DateAdd, DatePart

Sub Main
    Debug.Print DateDiff("yyyy",#1/1/1990#,#1/1/2000#) ' 10
End Sub