Add one line note about 0000-00-00 date/datetime (#783)
Add one line note about 0000-00-00 date/datetime (#783)

Fixes #741

Signed-off-by: INADA Naoki <2ae1edce4310a280a5d8198df0ea2c7ec8d870d8@gmail.com>
go-sql-driver/mysql,VividCortex/mysql,Go-SQL-Driver/MySQL,VividCortex/mysql,methane/mysql,methane/mysql