Update date field

Question

Hi All,
I need to update datafiled in a manner where it display only month and year.
Date
05-APR-09
05-MAY-09
05-FEB-09
05-MAY-09
08-MAY-09
07-MAY-09
10-MAY-09
woule resemble like below one.
Date
Apr09
May09
Feb09
May09
May09
May09hare krishna

Answer 1

Hi,
Amit Beheria wrote:
Yes you are right, but I have a requirement, where , I need a single value coming out, when applied group by function. for example, I have purchase_date , category, amount_spent like field in a table, when I need to query which is the category, on which I spent maximum is bit difficult, because, then it returns many value, becuase a month can have many dates. in office, right now, otherwise, i would've paste the result set here.A lot of folks store the dates in a DATE column, and use something like TRUNC (dt, 'MONTH') (as Charred did, in the first reply to this thread) when they want to map everything from one calendar month into one value.
For example:
REATE TABLE     table_x
(     id     NUMBER (4)     PRIMARY KEY
,     dt     DATE
,     amt     NUMBER
INSERT INTO table_x (id, dt, amt) VALUES (301,  TO_DATE ('31-Mar-2010 00:00', 'DD-Mon-YYYY HH24:MI'),  10);
INSERT INTO table_x (id, dt, amt) VALUES (302,  TO_DATE ('31-Mar-2010 00:01', 'DD-Mon-YYYY HH24:MI'),  20);
INSERT INTO table_x (id, dt, amt) VALUES (401,  TO_DATE ('01-Apr-2010 07:30', 'DD-Mon-YYYY HH24:MI'),  30);
INSERT INTO table_x (id, dt, amt) VALUES (402,  TO_DATE ('02-Apr-2010 20:45', 'DD-Mon-YYYY HH24:MI'),  40);
SELECT       TO_CHAR ( TRUNC (dt, 'MONTH')
            , 'Mon YYYY'
            )     AS month
,       SUM (amt)     AS total_amt
FROM       table_x
GROUP BY  TRUNC (dt, 'MONTH')
ORDER BY  TRUNC (dt, 'MONTH')
;Output:
MONTH              TOTAL_AMT
Mar 2010                  30
Apr 2010                  70There are some valid reasons for not using DATEs, such as needing fractions of a second or timezone information. In those cases, use a TIMESTAMP instead of a DATE.
Never use a VARCHAR2 or a NUMBER to store date information.