C++ :: SQLite - Add All The Mileage Between Two Dates

I have a simple table in SQLite:

Column 1: vistDate (stored as date)
Column 2: mileage

As a test, I created one row,
visitDate = 03/02/2013
Mileage = 10

I want to be able to add all the mileage between two dates but in my SQLite query, it returns zero mileage if the first date is not in the same month.

I am inputting the dates in the dd/mm/yyyy format above. It works fine for

Date 1: 01/02/2013
Date 2: 04/02/2013

i.e. 10 miles is returned as answer

but if Date1: 30/01/2013 I get Null.

Here's the query:

SQLiteExec("SELECT SUM(mileage) FROM mileageTable WHERE visitDate BETWEEN '01/02/2013' AND '04/02/2013')