Have you considered using a Pivot table? Assuming your data is in a database
style format, then by adding another field to it that quesries the date for that
record and based on whether it is within the last 90 days or so you will be able
to filter on that alone and yet use all the power that pivot Analysis gives you.
Assuming your data has dates in Col A, then create another field and start with
=A2=(TODAY()-90) and copy down. This will give you TRUE for all records that
are within the last 90 days and this can be used as a filter in the Pivot table.

Some introductory links for Pivot tables

http://peltiertech.com/Excel/Pivots/pivotstart.htm

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Regards
Ken....................... Microsoft MVP - Excel
Sys Spec - Win XP Pro / XL 97/00/02/03

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It's easier to beg forgiveness than ask permission :-)
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"Frank Kabel" wrote in message
...
Hi
maybe something like
=SUMIF(A1:A1000,"=" & TODAY()-90,B1:B1000)

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Regards
Frank Kabel
Frankfurt, Germany


TylerMaricich wrote:
I'm a pilot trying to use excel 2002 to calculate my logbook, and
need to know how much of the time was in the last 90 days, I'm
looking for a formula that will help me sort, and add the data from
just the last 90 days.


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