Get First and last day of Month..

Question

Hi Friends,
I am trying to fetch First and Last day of a month and would like to implement that in the following code:
SELECT COALESCE(Date_A, Date_B, Date_C)
FROM dual
Here Date A and B are in Format of MM DD YYYY (March 14, 2008)
and Date C is like MM YYYY (March 2008)
How can I get the Date_C as March 1, 2008 OR March 31, 2008 format if Date A and B are NULL ?
Thanks!
Edited by: user11095386 on Apr 23, 2009 10:45 AM

Answer 1

Hi,
In my earlier message, I thought that you were starting with strings like '03 12 2009' and that you wanted to display them as 'March 12 2009'. If what you have is just the reverse, then just reverse the format strings in my first message. Add a comma, if you want one, in the appropriate format string.
I believe this is what you want:
COALESCE ( TO_CHAR ( TO_DATE ( Date_A, 'fmMonth DD YYYY'), 'MM DD YYYY')
         , TO_CHAR ( TO_DATE ( Date_B, 'fmMonth DD YYYY'), 'MM DD YYYY')
         , TO_CHAR ( TO_DATE ( Date_C, 'fmMonth YYYY'),    'MM DD YYYY')
         )Notice how, on the 3rd line, TO_DATE is called without DD in the format string:
TO_DATE ( Date_C, 'fmMonth YYYY')When you do this, the day defaults to the 1st of the month, so this is all you have to do to convert the VARCHAR2 'March 2009' to the DATE 01-Mar-2009.
If you want the last day of the month, not the first, when Date_C is chosen, then use LAST_DAY:
COALESCE ( TO_CHAR ( TO_DATE ( Date_A, 'fmMonth DD YYYY'), 'MM DD YYYY')
         , TO_CHAR ( TO_DATE ( Date_B, 'fmMonth DD YYYY'), 'MM DD YYYY')
         , TO_CHAR ( LAST_DAY ( TO_DATE ( Date_C
                                          , 'fmMonth YYYY'
             , 'MM DD YYYY'
         )