yogi_Count Instances of Names in Column A For A Specified Date (or all dates) In Column B

                                          Google Spreadsheet   Post  #1423
Yogi Anand, D.Eng, P.E.      ANAND Enterprises LLC -- Rochester Hills MI     www.energyefficientbuild.com.   Nov 17, 2013
post by Clare-Noel Holdinghaus question by ajta@0316 (http://productforums.google.com/forum/?zx=emvk7dhbcu1y#!mydiscussions/docs/oMozBKn-1mY)
ive read your post.. will this also work on TIMESTAMP, but i just want to filter the EXACT DATE regardless of the time?

10/29/2013	ubert
10/28/2013	ubert
10/30/2013	jessica
10/30/2013	ubert
10/30/2013	susan
10/30/2013	grace
10/30/2013	Aguilar
10/28/2013	ubert
10/31/2013	jhimpeter
10/26/2013	jessica
10/26/2013	angela
10/28/2013	ubert
10/28/2013	ubert
11/1/2013	marc
10/31/2013	jhimpeter
10/26/2013	jhimpeter
11/1/2013	jessica
11/1/2013	marc

Count how many times the name appeared on a specific date.. expected result will be something like:

jessica	4
marc	8
Ubert	16
Jhimpeter	5

may first idea would be:

given COL A = timestamp

        COL B = username

D2=unique(B:B)

E2=countif(B:B, D2)

however this would filter all entries regardless of the date... I would like countif based on specific date..

thanks!!

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following is a solution to a bit more generalized problem