Thanks for your comment, I really dont have a clue how to do all that, I’m only a beginner with MySQL unfortunately so I dont know how to do what you have said
You want to do it all in MySQL? PHPMyAdmin lets you import comma separated value files. But I have no idea if you can specify to import only one value.
Maybe you could create a temporary table to load the CSV file, and then copy the emails to the email table?
i would create a table with all the columns, then do a LOAD DATA INFILE using the text file, then create my desired table with just the email column, and do a INSERT INTO SELECT, then drop the uploaded table