Jeg kiggede lidt rundt da jeg ved intet om mySQL, men fandt en side måske du kan brug:
For those who need to convert from (MM/DD/YYYY)
format to (YYYY/MM/DD the ansi standard used in
mysql) (it seems to have been rather rudely left
out) without using scripting languages to do so,
you can do this...
CONCAT( SUBSTRING_INDEX( MM-DD-YYYY-Date, '/', -
1) , '/', SUBSTRING_INDEX( MM-DD-YYYY-Date, '/',
1), '/', SUBSTRING_INDEX(SUBSTRING_INDEX(MM-DD-
YYYY-Date, '/',2), '/', -1))
Note, change the '/' to whatever deliminator you
are using in your date. This works well to
convert the date to the format that mysql will
understand and work properly with. To convert
from the ansi standard date format (YYYY/MM/DD)
back to (MM/DD/YYYY) use the DATE_FORMAT function.
http://www.mysql.com/doc/en/Cast_Functions.html