MySQL Insert with value from previous row / MySQL triggers fire multiple times, how to limit them

Question

I've created a log trigger that runs every time my other table is being updated, it creates a row with log informations. Unfortunately the system I am working on performs one operation as multiple queries so my trigger is fired much more times than I need. This is an output from one operation.

During parameter update the system firstly perform separate DELETE query for each row with matched parameter and product_id and then perform INSERT statement for every parameter that match product_id. Because of that the trigger is fired for every query with parameter (7 times per INSERT in this product, but there are cases with 100+ parameters per product)

So, I want to reduce it to one row per operation, the last row. In the future parameters will be updated by Webservice API so I am looking for a simpler solution than making events with JS and PHP. I thought about subtracting NOW() with the date from previous row (with the same product_id) and if the result is slightly different or the same I delete the previous row. I saw posts and articles with lag() but it seems that it's not working with INSERT INTO queries. If you have any suggestion, please, help

Answer 1

https://dev.mysql.com/doc/refman/8.0/en/faqs-triggers.html#faq-mysql-have-trigger-levels says:

Does MySQL 8.0 have statement-level or row-level triggers?

In MySQL 8.0, all triggers are FOR EACH ROW ; that is, the trigger is activated for each row that is inserted, updated, or deleted. MySQL 8.0 does not support triggers using FOR EACH STATEMENT .

It doesn't seem like a trigger of the type MySQL supports can work easily for your case. I recommend you simply execute your inserts, then execute the deletions you want to do from your application, not from triggers.