You can use sumproduct for multiple criteria
For your specifics here, try something like this:
=SUMPRODUCT(($B$11:$B1000=--"15 Apr 2010")*($C$11:$C1000=""))
where
criteria 1 is $B$11:$B1000= --"15 Apr 2010"
(shows an unambiguous way to use when it comes to dates data)

criteria 2 is $C$11:$C1000=""
(range="") is equivalent to countblanks

The multiplication of the 2 criteria gives an "AND" result, where both
criteria are satisfied. Success? hit the YES below
--
Max
Singapore
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"Molasses26" wrote:
I have a table that has meter# , date, and usage in colums A, B and C.
I use a formula =sumif($B$11:$B1000,"="[date],$C$11:$C1000) to total up the
amount of usage for each day. But what I want to do is count the number of
blanks in column C for each date.
So "if $B$11:$B1000,"="[date] then countblank($C$11:$C1000)" is kind of what
I'm shooting for but I can't wrap my brain around how to do it.
I would like to report that on 4/1 we had 1,912 usage and 4 meters did not
report (were blank).
Thanks!