In fact, a friend of ours in the forum asked the same question in 2007: Can I restore deleted memberships from mysql backup? , my answer was as follows : of course you can bring them back , I’m sure you don’t just take the members
back up , you probably just want the backup whole and you just want the members back , there are a few rules to follow :
You need to delete the current line from mysql, because it will give an error while installing.
2. then you have to open all the backups with notepad and separate from the person that the members started with (I was saving and reloading as .sql, I even added the new members to the regular members, but no one understood anything from the explanation I made even let me explain it here:

I took a backup of only the members of one of the two different phpbb forums and added them to the members of the other as follows:

1.restores the members to be moved (the extension is made into txt)
2.by saying file open in excel It is imported into excel format (by the way, we need some advanced excel knowledge because we only need id, name, password(in the form of Md5) and emails) so we will ensure that these are in separate columns
3.A new user is registered in the forum to be migrated (for example : in the test name)
4th attempt is activated and INSERT INTO `phpbb_users` ….. The entire record in the form is taken and pasted into notepad (the extension is saved as .txt) and it is opened in Excel again.. The columns that should be separate in the article are considered here again
5.then : the id of the experiment is taken into account, let’s say 3965 is the key number, that is, 1. The ids of the items in the article are continued as one more of this (it can be done very easily in Excel)
6. and the id, name, password (in the form of Md5) and email columns of the members to be moved are taken and 4. The essay in the article is pasted under the id, name, password, and email columns (we also do this in excel)
7.The essays are copied to the other columns that remain empty, by the way, it is necessary to pay attention that the theme and language persons are the same as the essay
8. Here again, with advanced excel knowledge ( =CONCATENATE() ) function, separate columns can be combined and goodbye.

Invented and implemented the method: Velociraptor