Ying Lu <ying_lu(at)cs(dot)concordia(dot)ca> writes:
> at the beginning of the data population, we do not know the value of
> "col3"; values for "col3" are input throught GUI. Therefore, when I use
> MySQL, the default values I gave is "0000-00-00".
Use NULL. That's what it's for.
regards, tom lane