Counting no of days between dates

Hi,
 I am working on leave module. we maintain all holidays related dates in holidaydatadase list . when leave is applied the start date and enddate is menctioned . so we need to count no of days between the start and end dates
 - holidays .

 For this i wrote a caml query

" +FromDate  + "" + Todate  + ""

holiday is a column in holidaydatabase list.

i am getting zero values when this query is executed
can any on help