Error while inserting date – Incorrect date value:

As MySql accepts the date in y-m-d format in date type column, you need to STR_TO_DATE function to convert the date into yyyy-mm-dd format for insertion in following way:

INSERT INTO table_name(today)
VALUES(STR_TO_DATE('07-25-2012','%m-%d-%Y'));

If you want to select the date in different format other than Mysql format, you should try DATE_FORMAT function

SELECT DATE_FORMAT(today, '%m-%d-%y') from table_name;