did you happen to see how mysql stores DATETIME values?
hint: they are ~not~ stored as yyyy-mm-dd strings
similarly, timestamp values are not stored as yyyy-mm-dd hh:mm:ss strings
instead, they are stored as unix epoch integers, and when you select them, they are just displayed as yyyy-mm-dd hh:mm:ss strings
moral of the story: internal storage format is often quite different from displayed format