HQL Query date query for records in a day

First of all, the database is stored in the date (including time) now want to get a day of all the records in a field and then we need to query the record of a day

Pass the string, and then handle the string day in the form of "2012-01-01" if the return value is null, set to 0.

	@Resource
	private sessionfactory sessionfactory;
	
	Public Double Getmoneyinofday (String day) {
		string start = day+ "00:00:00";
		String end = day+ "23:59:59";
		String hql= "Select sum (b.moneyin) from Bill b where b.date >= '"
			+start+ "' and B.date '" <= ' ";
		Query q = sessionfactory.getcurrentsession (). CreateQuery (HQL);
		Double d = (double) q.uniqueresult ();
		return d==null?0:d;
	}