What about a calculated field based on the decimal portion of the internal time representation. Such as:

Create Table #test (

TestDate varchar(9)

)

Insert into #test

Select '0'

union

select '00:22'

union

select '00:39'

union

select '02:19'

union

select '-03:06'

Select TestDate,

case RTRIM(TestDate)

When '0' then 0

else

case left(TestDate,1)

when '-' then CONVERT(decimal(9,6),convert(datetime,substring(RTrim(TestDate),2,8),114)) * -1

else CONVERT(decimal(9,6),convert(datetime,RTrim(TestDate),114))

end

end as SortDate

from #test

where TestDate <> '0'

order by SortDate

[/code]

Output:

-03:06-0.129167

00.000000

00:220.015278

00:390.027083

02:190.096528