Set flag for a set of records

Question

Hi
I have a table that stores requests raised by employees as below
name Request_ID date status
ABC 112 05-Dec-11 rejected
ABC 786 06-Dec-11 approved
ABC 987 07-Dec-11 rejected
ABC 119 08-Dec-11 approved
MNP 221 09-Nov-11 rejected
MNP 666 10-Nov-11 approved
MNP 221 11-Nov-11 rejected
MNP 999 12-Nov-11 approved
RST 99 23-Dec-11 rejected
RST 101 24-Dec-11 approved
RST 876 25-Dec-11 rejected
RST 127 26-Dec-11 approved
I need to check the status of the latest request of each employee and set the flag of all his requests as -
‘A’ if the latest request status is ‘approved’
‘B’ if the latest request status is ‘rejected’
The resultset should be something like -
name Request_ID date status Flag
ABC 112 05-Dec-11 rejected A
ABC 786 06-Dec-11 approved A
ABC 987 07-Dec-11 rejected A
ABC 119 08-Dec-11 approved A
MNP 221 09-Nov-11 rejected B
MNP 666 10-Nov-11 approved B
MNP 221 11-Nov-11 approved B
MNP 999 12-Nov-11 rejected B
RST 99 23-Dec-11 approved A
RST 101 24-Dec-11 approved A
RST 876 25-Dec-11 rejected A
RST 127 26-Dec-11 approved A
Could you please help me in framing this SQL. Use of any analytical function would be helpful
Regards
-pankaj

Answer 1

Hi, Pankaj,
Welcome to the forum!
910543 wrote:
Hi
I have a table that stores requests raised by employees as belowWhenever you have a problem, please post CREATE TABLE and INSERT statements for your sample data, so that the people who want to help you can re-create the probelm accurately and test their ideas. since this is your first message, I'll do it for you:
CREATE TABLE     table_x
(     name           VARCHAR2 (5)
,     request_id     NUMBER
,     dt          DATE          -- DATE is not a good column name
,     status          VARCHAR2 (10)
,     CONSTRAINT  x_uk     UNIQUE (name, dt)
INSERT INTO table_x (name, request_id, dt, status) VALUES ('ABC', 112, TO_DATE ('05-Dec-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('ABC', 786, TO_DATE ('06-Dec-2011', 'DD-Mon-YYYY'), 'approved');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('ABC', 987, TO_DATE ('07-Dec-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('ABC', 119, TO_DATE ('08-Dec-2011', 'DD-Mon-YYYY'), 'approved');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('MNP', 221, TO_DATE ('09-Nov-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('MNP', 666, TO_DATE ('10-Nov-2011', 'DD-Mon-YYYY'), 'approved');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('MNP', 221, TO_DATE ('11-Nov-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('MNP', 999, TO_DATE ('12-Nov-2011', 'DD-Mon-YYYY'), 'approved');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('RST',  99, TO_DATE ('23-Dec-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('RST', 101, TO_DATE ('24-Dec-2011', 'DD-Mon-YYYY'), 'approved');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('RST', 876, TO_DATE ('25-Dec-2011', 'DD-Mon-YYYY'), 'rejected');
INSERT INTO table_x (name, request_id, dt, status) VALUES ('RST', 127, TO_DATE ('26-Dec-2011', 'DD-Mon-YYYY'), 'approved');
COMMIT; name Request_ID date status ...If those are all the columns in the table, and you want to display a flag column, you can do something like this:
SELECT     name
,     request_id
,     dt
,     status
,     CASE  FIRST_VALUE (status) OVER ( PARTITION BY  name
                           ORDER BY     dt     DESC
          WHEN  'approved'     THEN  'A'
          WHEN  'rejected'     THEN  'B'
     END          AS flag
FROM     table_x
;If the table has a flag column, and you need to populate it, you can use the query above in a MERGE statement. (You may be better off not actually storing the flag, however, if it's hard to keep up to date.)
MNP 221 09-Nov-11 rejected
MNP 666 10-Nov-11 approved
MNP 221 11-Nov-11 rejected
MNP 999 12-Nov-11 approved ...
I need to check the status of the latest request of each employee and set the flag of all his requests as -
‘A’ if the latest request status is ‘approved’
‘B’ if the latest request status is ‘rejected’
The resultset should be something like -
name Request_ID date status Flag
MNP 221 09-Nov-11 rejected B
MNP 666 10-Nov-11 approved B
MNP 221 11-Nov-11 approved B
MNP 999 12-Nov-11 rejected BIn the original data, the status for the row with request_id=999 was 'approved'. Is there a typo somewhere?
Edited by: Frank Kulash on Jan 26, 2012 10:57 PM