sum only records of today's month

[#1]

Hi !

i am trying to create an expression that will sum a field but only when the record's date is today's month.

this is what i wrote and it's incorrect:

=sum({<MonthName(date) = {"monthName(Today())"} >} clicks)

for example:

date	clicks
10/1/2013	10
10/2/2013	3
10/3/2013	7
10/4/2013	8
10/5/2013	3
9/1/2013	2
9/2/2013	8
9/3/2013	3
9/4/2013	9
9/5/2013	2

i want the expression to sum only the records from October.

[#2]

Then if it works, what does not work is to use a field in the database function sets:

= sum ({<CtaMov = {$(=maxstring(Filtro))}>} Value)

where filter is a field in a table that one of your values ​​is by example

640*, 641*    or     640,641

and the result will be 10.