How can I group by date time column without taking time into consideration

Question

I have a bunch of product orders and I\'m trying to group by the date and sum the quantity for that date. How can I group by the month/day/year without taking the time part

Answer 1

GROUP BY DATEADD(day, DATEDIFF(day, 0, MyDateTimeColumn), 0)

Or in SQL Server 2008 onwards you could simply cast to Date as @Oded suggested:

GROUP BY CAST(orderDate AS DATE)