https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html
用法
http://www.mysqltutorial.org/mysql-insert-or-update-on-duplicate-key-update/
When you insert a new row into a table if the row causes a duplicate in [UNIQUE](http://www.mysqltutorial.org/mysql-unique/)
index or [PRIMARY KEY](http://www.mysqltutorial.org/mysql-primary-key/)
, MySQL will issue an error.
However, if you specify the ON DUPLICATE KEY UPDATE
option in the INSERT
statement, MySQL will update the existing row with the new values instead.