"masterdineen" wrote:
I have the following equation =AVERAGEIF(SUPPORT!K9:K99, "0")
support!K9:K99 being number of daydiff.
I want to select the daydiff values based on another date column,
that only has the current month and year. ie Aug(8) & 2012

=AVERAGEIFS(support!K9:K99,support!K9:K99,"0",
support!D9:D99,"="&DATE(2012,8,1),support!D9:D99, "<="&DATE(2012,8,31))

And in case there might be no qualifying cells:

=IFERROR(AVERAGEIFS(support!K9:K99,support!K9:K99, "0",
support!D9:D99,"="&DATE(2012,8,1),support!D9:D99, "<="&DATE(2012,8,31)),0)