create table T(rectime datetime)
insert T select '2006-12-22 16:44:18.000'
union all select '2006-12-22 16:44:17.000'
union all select '2006-12-22 16:44:14.000'
union all select '2006-12-22 16:44:13.000'
union all select '2006-12-22 16:44:11.000'
union all select '2006-12-22 16:44:10.000'
declare @tb table(rectime datetime)
declare @beg_DT datetime, @end_DT datetime
select @end_DT=max(rectime) from T
select @beg_DT=min(rectime) from T
while @beg_DT<=@end_DT
begin
if not exists(select * from T where rectime=@beg_DT)
insert @tb select @beg_DT