I can't start or stop mysql-server . Is it because mariadb and mysql are two

mysql version like this

mysql -V mysql Ver 15.1 Distrib 10.1.44-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2

I want to start mysql.service

systemctl start mysql.service Failed to start mysql.service: Unit mysql.service not found.

service mysql start Failed to start mysql.service: Unit mysql.service not found.

apt-get install mysql-server Reading package lists… Done Building dependency tree Reading state information… Done You might want to run ‘apt --fix-broken install’ to correct these. The following packages have unmet dependencies: mariadb-server : Depends: mariadb-server-10.1 (>= 1:10.1.44-0ubuntu0.18.04.1) but it is not going to be installed mysql-server-5.7 : Depends: mysql-client-5.7 (>= 5.7.31-0ubuntu0.18.04.1) but it is not going to be installed Depends: mysql-server-core-5.7 (= 5.7.31-0ubuntu0.18.04.1) but it is not going to be installed Depends: libevent-core-2.1-6 (>= 2.1.8-stable) but it is not going to be installed E: Unmet dependencies. Try ‘apt --fix-broken install’ with no packages (or specify a solution).