Help in designing SQL

Question

Hi All,
I need little help in designing SQL. My input and output data is given below:
Input
Key
Date_1
Date_2
Key1
2/14/2011 5:22:35 PM
2/22/2011 3:05:13 PM
Key1
2/24/2011 1:48:07 PM
5/24/2011 4:50:16 PM
Key1
2/24/2011 1:48:59 PM
4/25/2011 3:36:19 PM
Key1
5/24/2011 5:18:19 PM
6/16/2011 3:17:40 PM
Key1
6/16/2011 3:25:42 PM
6/24/2011 1:33:13 PM
Key1
6/17/2011 1:12:54 PM
6/25/2011 5:55:55 PM
Output
Key
Date_1
Date_2
Key1
2/14/2011 5:22:35 PM
2/22/2011 3:05:13 PM
Key1
2/24/2011 1:48:07 PM
5/24/2011 4:50:16 PM
Key1
5/24/2011 5:18:19 PM
6/16/2011 3:17:40 PM
Key1
6/16/2011 3:25:42 PM
6/25/2011 5:55:55 PM
Here out of 2nd and third record of input, output is 2nd record of output and 5th and 6th record of input would come out as  4th record of output. Basically, if we overlapping duration between Date_1 and Date_2, we need to take min of Date_1 and max of Date_2 for that overlapping records. In case of no overlapping, we would simply output input record like  record 1 and 4 of input.
Out of
Key1
2/24/2011 1:48:07 PM
5/24/2011 4:50:16 PM
Key1
2/24/2011 1:48:59 PM
4/25/2011 3:36:19 PM
2/24/2011 1:48:07 PM was  min of above 2 and 5/24/20114:50:16 was max of above 2.
Similarly in other overlapping scenario:
Key1
6/16/2011 3:25:42 PM
6/24/2011 1:33:13 PM
Key1
6/17/2011 1:12:54 PM
6/25/2011 5:55:55 PM
6/16/2011 3:25:42 PM  was min of above 2 and 6/25/2011 5:55:55 PM was max of above 2.
Pls help.
Thanks.

Answer 1

Hi Frank.,
The above logic with NVL is not working.
My input sample is:
Key
Date_1
Date_2
Key1
2/14/2011 5:22:35 PM
2/22/2011 3:05:13 PM
Key1
2/24/2011 1:48:07 PM
5/24/2011 4:50:16 PM
Key1
2/24/2011 1:48:59 PM
Key1
5/24/2011 5:18:19 PM
6/16/2011 3:17:40 PM
Key1
6/16/2011 3:25:42 PM
6/24/2011 1:33:13 PM
Key1
6/17/2011 1:12:54 PM
6/25/2011 5:55:55 PM
I am giving create and insert statement below for creation of above data. Please see if you can help me:
CREATE TABLE test1
  KEY1          NUMBER     ,   
  DATE_1               DATE ,          
  date_2              DATE
insert into test1
values(1, TO_TIMESTAMP ('2/14/2011 5:22:35 PM', 'MM/DD/YYYY HH:MI:SS AM'),TO_TIMESTAMP ('2/22/2011 3:05:13 PM', 'MM/DD/YYYY HH:MI:SS AM')  ) ;
values(1, TO_TIMESTAMP ('2/24/2011 1:48:07 PM', 'MM/DD/YYYY HH:MI:SS AM'),TO_TIMESTAMP ('5/24/2011 4:50:16 PM', 'MM/DD/YYYY HH:MI:SS AM')  ) ;
values(1, TO_TIMESTAMP ('2/24/2011 1:48:59 PM', 'MM/DD/YYYY HH:MI:SS AM'), '' ) ;
values(1, TO_TIMESTAMP ('5/24/2011 5:18:19 PM', 'MM/DD/YYYY HH:MI:SS AM'),TO_TIMESTAMP ('6/16/2011 3:17:40 PM', 'MM/DD/YYYY HH:MI:SS AM')  ) ;
values(1, TO_TIMESTAMP ('6/16/2011 3:25:42 PM', 'MM/DD/YYYY HH:MI:SS AM'),TO_TIMESTAMP ('6/24/2011 1:33:13 PM', 'MM/DD/YYYY HH:MI:SS AM')  ) ;
values(1, TO_TIMESTAMP ('6/17/2011 1:12:54 PM', 'MM/DD/YYYY HH:MI:SS AM'),TO_TIMESTAMP ('6/25/2011 5:55:55 PM', 'MM/DD/YYYY HH:MI:SS AM')  ) ;
commit;
Expected output would be:
Output
Key
Date_1
Date_2
Key1
2/14/2011 5:22:35 PM
2/22/2011 3:05:13 PM
Key1
2/24/2011 1:48:07 PM
Key1
5/24/2011 5:18:19 PM
6/16/2011 3:17:40 PM
Key1
6/16/2011 3:25:42 PM
6/25/2011 5:55:55 PM
Thanks....