Try this array formula

=SUM(--(FREQUENCY(IF((A2:A100=--"2008-09-01")*(A2:A100<--"2008-09-06"),MATCH(A2:A100,A2:A100,0)),ROW(INDIRECT("1:"&R OWS(A2:A100))))0))

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HTH

Bob

"Guidu" wrote in message
...
imagine a range like this:

Actiondate volume
1-sep 2
1-sep 3
3-sep 5
5-sep 7
9-sep 6
etc

this constrains
Actiondate Actiondate
=1-sep <6-sep



I would like a function that counts the number of days between my contrain
that do not doble count de dates....in this example the answer would be 3

Thank you people very much....I am so gratefull for your help