Not 100% sure what you need, but, for example, this gives sales for the latest quarter for >=7AM and <8AM:
select *
from TicketItem
where s_item IN('Coffee', 'Espresso', 'Double Espresso', 'Decaf Espresso', 'Cappucino', 'Latte', 'Iced Coffee', 'sm coffee pot', 'lg coffee pot')
and dt_when >= dateadd(quarter, datediff(quarter, 0, getdate()), 0)
and hour(dt_when) = 7
Msg 195, Level 15, State 10, Line 15
'hour' is not a recognized built-in function name.
Ideas?