Access denied when trying to re-install lamp

Question

I'm trying to install LAMP on ubuntu 16.04. I had everything installed, but accidentally locked myself out of LAMP trying to get phpmyadmin working, I get Access denied for user 'root'@'localhost' with whatever I try.

I thought the easiest solution would be to uninstall all packages I installed to get LAMP working. I used sudo apt-get purge to uninstall all packages I installed. Now I'm installing all packages again but I get the same error when trying to install mysql. I try: sudo mysql_secure_installation and it asks me for the password for root. I tried leaving it empty, giving the passwords I think I set for root, but everything just returns the access denied message.

Trying to get into mysql with mysql -u root -p always returns the access denied message, I tried a solution by creating a file with CREATE USER 'root'@'localhost' IDENTIFIED BY '<password>'; and running sudo mysqld_safe --init-file=<path_to_file> but I still receive the access denied messages.

I'm thinking there is a file somewhere with the information, maybe the password, it needs. I tried a lot of other solutions too but nothing seems to work.

EDIT: I investigated further, and I tried starting the mysql service with the --skip-grant-tables flag to stop checking user privs. When I run mysql -u root it still tells me ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO). I think the problem hasn't to do with my password, but something else.

Answer 1

I managed to fix it by killing all mysql processes running: ps aux | grep mysql lists the processes and then killing them with sudo kill -9 [PID]. that allowed me to start a mysqld_safe process with the --skip-grant-tables flag and this allowed me to get into mysql with mysql -u root. Following this further to reset the password for root: https://help.ubuntu.com/community/MysqlPasswordReset

Also the password column has been changed to authentication_string in the user table in mysql_server 5.7 (latest version as of now).

After doing this I got it all installed and I can access phpmyadmin now!