Making file to run via Cronjobs

I was having issues with mySQL to find out all I needed was to update mySQL from 5.6 to 8.0+. well that became harder then it sounded since I was still running the Jessie version. With all that said, I now have things back up and running and I realized I forgot one file to backup. I you had helped me years ago to make a file that I could execute from a cronjob to run some mySQL commands to back up my databases. I’m now running the latest Turnkey stretch version.