Курсоры зло.
begin tran

create table #res (
	ID int not null identity(1, 1),
	[Date] datetime not null,
	Name varchar(100) not null,
	constraint	PKres		primary	key	( Id )
)

insert #res ([Date], Name) values ('20150611 10:00', 'Пупкин')
insert #res ([Date], Name) values ('20150611 12:00', 'Пупкин')
insert #res ([Date], Name) values ('20150611 10:30', 'Иванов')

select dateadd(day, datediff(day, 0, [Date]), 0) [Day], min([Date]) Start, Name
from #res
group by dateadd(day, datediff(day, 0, [Date]), 0), Name
order by min([Date])

rollback