What is the name of the process for synchronizing two MySQL tables?

[Spark]

Hello, I have two backups taken from a script in phpMyAdmin. I want to compare Backup A and Backup B and add the missing elements from each other. This process involves restoring deleted data. How can I do this? In short, I want the missing items from B to come from backup A. Backup B is the current database but some items have been deleted, while backup A has all the items from a previous backup. How can I synchronize A and B? What is the name of this process? Or how can I do it? Thank you.