use 0 as date/datetime zero value

[xiezhenye]

return 0 as zero value of date/datetime to tell difference from NULL and '0000-00-00'.
e.g. insert/update a NOT NULL date column, only '0000-00-00' or 0 is valid.

[julien-duponchelle]

That sound correct.

But I worry that will force people to handle this case in their code. What is the good usage of 0000-00-00?

What others think about it?

PS: it seem some tests still failed

[baloo]

Looks good to me, just need to make sure this is not a patch-level release. And it's shown in the changelog.

[julien-duponchelle]

@xiezhenye can you fix the tests? I will merge it after that

Thanks for the help

[xiezhenye]

MySQL 5.6 tests passed. MySQL 5.7 tests seems failed to start test instance.