docker ps
CONTAINER ID        IMAGE                COMMAND                CREATED             STATUS              PORTS                    NAMES
e5edc5732d78        mysql:latest         "/ mysq   49 minutes ago      Up 33 minutes>3306/tcp   mysql

docker exec コマンドで接続。

$ docker exec -it e5edc5732d78 bash

$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.24 MySQL Community Server (GPL)

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