How to pull the trigger?

Question

MySQL

There is a table in which one of the columns is defined as unique. When inserting a duplicate value, you need to catch the primary key and throw the table into the log. I think it is necessary to cause the trigger, function or procedure. I tried to insert via INSERT INTO ... ON DUPLICATION KEY UPDATE `id` = `id` on the table, I hung the AFTER UPDATE trigger, but when updating the id itself, it looks like the update is cut during optimization and is not performed at all, therefore the trigger does not work.

Answer 1

Either BEFORE UPDATE, but the trigger will have to check the uniqueness of the added value.
Or add another column like `errors` and do ON DUPLICATE KEY UPDATE `errors` = `errors`+1. Then in the AFTER UPDATE trigger you can simply check for OLD.`errors` != NEW.`errors`.