Why is greater the 1st of month not working?

[tra1a]

formula:
=COUNTIF(WIA!D:D,"<="&DATE(2011,9,31))-COUNTIF(WIA!D:D,"<="&DATE(2011,9,1))

It is not working for 9/1/2011. Why?

Thanks.

 

[Jonmo1]

Because you subtracted the ones that are less than OR Equal to 9/1/2011

Try changing

=COUNTIF(WIA!D:D,"<="&DATE(2011,9,31))-COUNTIF(WIA!D:D,"<="&DATE(2011,9,1))
to
=COUNTIF(WIA!D:D,"<="&DATE(2011,9,31))-COUNTIF(WIA!D:D,"<"&DATE(2011,9,1))

 

[Scott Huish]

Another way:

=SUMPRODUCT(--(TEXT(WIA!D1:D5000,"mmyyyy")="092011"))

Note you can't use whole columns with SUMPRODUCT in versions of Excel prior to XL2007.