mysql -u root -p

Taille des bases :

SELECT table_schema AS "Database Name",
ROUND(SUM(data_length + index_length) / 1024 / 1024, 2) AS "Size in (MB)"
FROM information_schema.TABLES GROUP BY table_schema; 

Taille des tables d'une base :

SELECT table_name AS "Table Name",
ROUND(((data_length + index_length) / 1024 / 1024), 2) AS "Size in (MB)"
FROM information_schema.TABLES WHERE table_schema = "ma-base" ORDER BY (data_length + index_length) DESC;

Taille physique :

du -h /var/lib/mysql