I do not want confirmation of my site member's e-mail address.
When the Member Item is published, I activate it myself.

That's why some people enter the wrong e-mail address. For example @gmaail.com, @gmaill.com etc.

With which command from the data base can I update this incorrect [email protected] part to ...@gmail?

Best way is to do it on database in item & user tables.

How to do it on database in item and user tables. ?

Which code can I use?

You may find many sql examples om google or stackoverflow