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 use DB_NAME;.

While in MySQL CLI, import the sql file via source /path/to/file.sql.

Done