You can redirect a SQL script through a mysql client by running:

mysql -uroot -prootpass -D mydatabase < /my/file/location.sql

Suppose you’re running MySQL or MariaDB in a container (e.g. mariadb:5.5 or mysql:8). You can do the same thing:

docker exec -i <container id> mysql -uroot -prootpass -D mydatabase < /my/file/location.sql

Note that this requires -i instead of the more normal -it you’d use when running. I believe any time you’re looking to pass in a finite stream (e.g. you’re redirecting something into the container), you don’t want to use -t.