Does mysql UPDATE inserts the values if it doesn't exist?

Question

UPDATE items SET name = 'haha' WHERE id = '12'

I'm curious if update also inserts the values if the where condition fails. I've read on w3schools that update only updates existing data on the database but on my script it's automatically inserting rows with the data. I am wondering if it might be a bug in the script or that's just how UPDATE works on mysql.

Answer 1

No. If, in your example, there's no entry with id = 12 in the database, the query will return "no rows affected". An update will never create a new entry in MySQL.

EDIT: although update won't create a new entry, it may include default/automatic values set up in your database schema (current timestamp, for instance).

Answer 2

NO. Update does not insert a value if the value doesn't exist in table. Please check if the script checks if the status of the update and makes another call to DB to insert the data.