declare @time_1 datetime
declare @startTime datetime
declare @endTime datetime
set @time_1 = '2009-03-05 00:00:00.001' 
set @startTime = '2009-03-04 00:00:00.00'
set @endTime = '2009-03-04 23:59:59.999'
Print '@startTime is ' + convert(char(23),@startTime,121)
Print '@time_1 is ' + convert(char(23),@time_1,121)
Print '@endTime is ' + convert(char(23),@endTime,121)
If @time_1 between @startTime and @endTime
  print 'True'

declare @time_1 datetime
set @time_1 = '2009-03-05 00:00:00.001' 
If @time_1 >= '2009-03-04' and @time_1 < '2009-03-05' -- time portion defaults to zeroes
  print 'True'
else
  print 'False'