MySQL: update without changing data, possible?

问题

Is it possible in MySQL to update a row, without changing any data?

I just need a trigger to do its work, but the data should not be changed.

Of course I could do an update and then another update, but the trigger is quite slow (deletes and inserts 500 rows everytime) and I have to update thousands of rows, so I'd rather not do it twice.

I could also just update a dummy field with NOW(), but I'm just curious if it's possible without 'tricks'.

回答1:

How about:

UPDATE table SET id=id WHERE ...

回答2:

You should just be able to run an UPDATE command with the same data that already exists in the row. No data will change, but the trigger will still fire.

来源：https://stackoverflow.com/questions/7408506/mysql-update-without-changing-data-possible