Combine both the query

Question

Hi all,
I am monitoring the flight information message.
Now we plan to alert a message if the flight information message were not get last 5 minutes comparewith Sysdate(Current system date and time).
Here the query :
SELECT MESSAGE,MESSAGE_DATE_TIME FROM UMESSAGE
Message Message_Date_Time
DUBAI 24/02/2009 11:39:16
ATHENS 24/02/2009 11:30:03
For example now the current date_time is 24/02/2009 11:45:16
The last message we got is 24/02/2009 11:39:16
After that message we did not get any message.It is almost more than 5 minutes.
Now I want to combine both the query .
SELECT SYSDATE FROM DUAL
SELECT MESSAGE,MESSAGE_DATE_TIME FROM UMESSAGE
how will I get it?
Please help.

Answer 1

Hi Rahul,
SQL> with umessage as (select 'DUBAI' message
                         ,to_date('24/02/2009 11:39:16', 'dd/mm/yyyy hh24:mi:ss') message_date_time
                    from dual
                  union all
                  select 'ATHENS' message
                         ,to_date('24/02/2008 11:30:03', 'dd/mm/yyyy hh24:mi:ss') message_date_time
                    from dual)
-- end of test data                   
select case
          when (sysdate - max(message_date_time)) * 24 * 60 > 5 then 'Alert'
          else 'Msgs Comming'
       end
  from umessage
CASEWHEN(SYS
Msgs Comming
1 row selected.Hint: We haven't heard from Athens in a year.
Regards
Peter