Hi,
PFB the output for purging
/# apt purge mysql-client mysql-server
Reading package lists… Done
Building dependency tree
Reading state information… Done
Package ‘mysql-client’ is not installed, so not removed
Package ‘mysql-server’ is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 45 not upgraded.
And also the output for
dpkg -l “mysql”|grep ii
ii php-mysql 1:7.0+35ubuntu6 all MySQL module for PHP [default]
ii php7.0-mysql 7.0.22-0ubuntu0.16.04.1 amd64 MySQL module for PHP
Then i installed the percona 5.5