This is most commonly used tool to visual inspect mysql databases with drupal, so there is a good chance you will want to use it with docker. So if you don't have it already installed with your drupal compose and you are building it from scratch you can manually add it. Do:

IF you want for some reason start from scratch and make new DB or anything else regarding mysql queries, you should first find out the name of your DB container and then with that name run command below and you will have access to SQL and you can then drop and recreate DB.

To see all containers adding the -a flag to "docker ps" will show all containers. 

docker ps -a

When you are sure you want to remove them all, first stop them all then remove them all

docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

For final cleanup do this

If you are using docker and mysql and getting  something like 

If you want to have simple and quick drupal 8 with just mysql installation with docker and not running docker compose you need to build 2 containers. One for mysql and other for drupal. First build mysql as we are going to link that to drupal one.