declare
@datetime datetimeoffset = '2012-10-25 00:00:00.000 +04:30'
select
case
when (DATEPART(TZ, @datetime) <> 0 and DATEPART(TZ, @datetime) is not null OR CONVERT(TIME(0),@datetime) <> '00:00:00')
then 0
when (DATEPART(TZ, @datetime) = 0 and @datetime <> '')
then 1
when (DATEPART(TZ, @datetime) is null)
then NULL
end as Precision