Before Datetime

Question

I have a form with datetimepicker1 and datagridview .

In the database one table named purchace

purid	purno	purdate	itemid	purqty	putgtotal	balance

I want to select itemname ,sum(purqty),sum(balance) from purchace where purdate is less than the selected date from datetimepicker1 and this will displayed in datagridview. plz help?