How to Distinctcount for lastmovement of each elem

helo i have a problem to get the distinctcount:My fact table:Elem DateMov------ ----------Elem 1 20140113Elem 2 20140215Elem 3 20140520Elem 1 20141011for a range date {null:20140230} i need return 2 elemsfor a range date {null:20140810} i need return 3 elemsfor a range date {null:20141020} i need return 3 elemsI need make the count with the last movement of each elem in the rage of date