SELECT table_schema AS "Database",
SUM(data_length + index_length) / 1024 / 1024 / 1024 AS "Size (GB)"
FROM information_schema.TABLES GROUP BY table_schema;
+--------------------+------------------+
| Database | Size (GB) |
+--------------------+------------------+
| db1 | 311.224670410156 |
| db2 | 149.395034790039 |
+--------------------+------------------+
Dr. Ogg