Help Date function

Question

Hi,
I am having a table with start_date column with varchar and the data is like '01/06/2000'. I want to convert it to date date type and update the date to '01-JUN-2000'. If it is possible with the same column then it is ok or i can even create a separeate column with date datatype but how to update '01/06/2000' to '01-JUN-2000'. This is urgent if any one can help it will be appreciated.
Thanks
Srinivas

Answer 1

SQL> -- If your data is like this:
SQL> SELECT start_date
  2  FROM   your_table
  3  /
START_DATE
01/06/2000
SQL> -- You can just display your existing
SQL> -- data in a different format:
SQL> SELECT TO_CHAR (TO_DATE (start_date, 'DD/MM/YYYY'),
  2                           'DD-MON-YYYY')
  3  FROM   your_table
  4  /
TO_CHAR(TO_
01-JUN-2000
SQL> -- or:
SQL> ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YYYY'
  2  /
Session altered.
SQL> SELECT TO_DATE (start_date, 'DD/MM/YYYY')
  2  FROM   your_table
  3  /
TO_DATE(STA
01-JUN-2000
SQL> -- Or, to add a new column of date data type:
SQL> ALTER TABLE your_table
  2  ADD (new_start_date DATE)
  3  /
Table altered.
SQL> -- To update the new column:
SQL> UPDATE your_table
  2  SET    new_start_date =
  3         TO_DATE (start_date, 'DD/MM/YYYY')
  4  /
1 row updated.
SQL> -- To display the new column in the desired format:
SQL> SELECT TO_CHAR (new_start_date, 'DD-MON-YYYY')
  2  FROM   your_table
  3  /
TO_CHAR(NEW
01-JUN-2000
SQL> -- or
SQL> ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YYYY'
  2  /
Session altered.
SQL> SELECT new_start_date
  2  FROM   your_table
  3  /
NEW_START_D
01-JUN-2000