Add a Date column

Question

I want to add a column to the end of a existing Table that has data in it. I need the column to contain DATE information and then after inserting the column I need to make all the rows values for that new added column to be in this format:
Month-Year there is no need for an exact Date format like: 01/01/2008 TIME, just MM/YYYY
I think this has worked for me in the past, but I am not sure about the DATE parts that I want and I am not sure how to insert say MARCH/2009 into all the rows, help would be appreciated, thanks!
alter Table Y775.TABLE
add
SPEND_GROUP DATE;
COMMIT;

Answer 1

Hi,
You're on the right track: ALTER TABLE is the way to add a column. You can find the syntax in the [SQL Language manual|http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/index.htm#A].
DATE columns always have days, hours, minutes and seconds. For this particular column, always use 1 for the day, and 00 for the hours, minutes and seconds. TRUNC (dt, 'MM') is an easy way to keep the year and month from dt, but set the other parts to '01 00:00:00', like you want. Add a CHECK constraint to make sure all the values you put into that column are like that:
CHECK (spend_group = TRUNC (spend_group, 'MM'))You don't have to display the parts of the DATE that you don't need.
For example:
TO_CHAR (spend_group, 'MM/YYYY')