This is a simple way of importing MySQL database in Docker.
In you Dockerfile you must have a shared folder. Shared folder is a directory in your host machine that is mounted to Docker instance.
Put the exported sql file in the shared folder.
Login to your Docker instance via
docker exec -it DOCKER_CONTAINER_ID bin/bash.
Login to MySQL via
mysql -u USERNAME -p.
While in MySQL CLI, create a database via
create database DB_NAME;.
While in MySQL CLI, use the database you just created via
While in MySQL CLI, import the sql file via