SQL Query - Hide lines - sql

Question

in my environment we use Altiris to control our asset and daily we had a policy that set status retired to computers that stay more than 45 days offline and turn back to active if this computer appers online on network.
The problem is sometimes (not for all devices) when the policy change the status it write on database two lines:
first with the current status and and another with the new status:
The same occur when the device go back to active status so when i try to SUM data to know how many devices was changed to retired or active by month the number doesn't make sense because for some devices we have two lines with 2 different status on same dataChanged
eg:
ComputerName Date Changed Status
001PROJNEW-VM 13/01/2015 17:33 Active
002PROJNEW-VM 11/09/2014 11:58 Retired
002PROJNEW-VM 07/10/2014 21:10 Retired
002PROJNEW-VM 07/10/2014 21:10 Active
003PROJNEW-VM 11/09/2014 11:58 Retired
003PROJNEW-VM 13/11/2014 03:27 Retired
003PROJNEW-VM 13/11/2014 03:27 Active
004PROJNEW-VM 06/04/2015 20:00 Retired
005PROJNEW-VM 11/09/2014 11:58 Retired
005PROJNEW-VM 09/10/2014 21:09 Retired
005PROJNEW-VM 09/10/2014 21:09 Active
005PROJNEW-VM 06/04/2015 20:00 Retired
006PROJNEW-VM 26/12/2014 20:00 Retired
006PROJNEW-VM 31/12/2014 05:34 Retired
006PROJNEW-VM 31/12/2014 05:34 Active
006PROJNEW-VM 06/01/2015 20:00 Retired
007PROJNEW-VM 11/09/2014 11:58 Retired
007PROJNEW-VM 27/12/2014 05:38 Retired
007PROJNEW-VM 27/12/2014 05:38 Active
007PROJNEW-VM 12/04/2015 19:50 Retired
008PROJNEW-VM 11/09/2014 11:58 Retired
008PROJNEW-VM 29/10/2014 05:44 Retired
008PROJNEW-VM 29/10/2014 05:44 Active
008PROJNEW-VM 06/04/2015 20:00 Retired
009PROJNEW-VM 11/09/2014 11:58 Retired
009PROJNEW-VM 17/09/2014 20:33 Retired
009PROJNEW-VM 17/09/2014 20:33 Active
009PROJNEW-VM 19/02/2015 20:00 Retired
010PROJNEW-VM 11/09/2014 11:58 Retired
010PROJNEW-VM 29/10/2014 05:44 Retired
010PROJNEW-VM 29/10/2014 05:44 Active
010PROJNEW-VM 06/04/2015 20:00 Retired
011PROJNEW-VM 05/04/2015 20:00 Retired
013PROJNEW-VM 20/02/2015 20:00 Retired
014PROJNEW-VM 06/04/2015 20:00 Retired
Basically what i need and actually i can't do is: if the hostname has two equal 'Date Changed' and two different 'status' bring in query result the last line for this Hostname and 'Date Changed'...
The result eg:
Nome do computador Date Changed Status
001PROJNEW-VM 13/01/2015 17:33 Active
002PROJNEW-VM 11/09/2014 11:58 Retired
002PROJNEW-VM 07/10/2014 21:10 Active
003PROJNEW-VM 11/09/2014 11:58 Retired
003PROJNEW-VM 13/11/2014 03:27 Active
004PROJNEW-VM 06/04/2015 20:00 Retired
005PROJNEW-VM 11/09/2014 11:58 Retired
005PROJNEW-VM 09/10/2014 21:09 Active
005PROJNEW-VM 06/04/2015 20:00 Retired
006PROJNEW-VM 26/12/2014 20:00 Retired
006PROJNEW-VM 31/12/2014 05:34 Active
006PROJNEW-VM 06/01/2015 20:00 Retired
007PROJNEW-VM 11/09/2014 11:58 Retired
007PROJNEW-VM 27/12/2014 05:38 Active
007PROJNEW-VM 12/04/2015 19:50 Retired
008PROJNEW-VM 11/09/2014 11:58 Retired
008PROJNEW-VM 29/10/2014 05:44 Active
008PROJNEW-VM 06/04/2015 20:00 Retired
009PROJNEW-VM 11/09/2014 11:58 Retired
009PROJNEW-VM 17/09/2014 20:33 Active
009PROJNEW-VM 19/02/2015 20:00 Retired
010PROJNEW-VM 11/09/2014 11:58 Retired
010PROJNEW-VM 29/10/2014 05:44 Active
010PROJNEW-VM 06/04/2015 20:00 Retired
011PROJNEW-VM 05/04/2015 20:00 Retired
013PROJNEW-VM 20/02/2015 20:00 Retired
014PROJNEW-VM 06/04/2015 20:00 Retired

Answer 1

If the dates are the same, there is no first or last record, so assuming you only have those 2 statuses, and you want the status always to be Active when 2 rows exist at the same time, you can just do it with min:
select
ComputerName
DateChanged
min(Status) as Status
from
YourTable
group by
ComputerName
DateChanged
If it's more complex, you can do similar things with row_number and ordering by the desired order of statuses.

Answer 2

Assuming you have, say, an id column that specifies the ordering, then you can use row_number():
select t.*
from (select t.*,
row_number() over (partition by computername, datechanged
order by id desc) as seqnum
from table t
) t
where seqnum = 1;
In your particular example, all the duplicates seem to be active. If that is the case, then:
select computername, datechanged,
(case when min(status) = max(status) then min(status)
when sum(case when status = 'Active' then 1 else 0 end) > 0
then 'Active'
else '***Unknown***'
end) as status
from table t
group by computername, datechanged;