mysql> SELECT sum( data_length + index_length ) / (1024 * 1024) "Size in MB" FROM information_schema.TABLES;
SELECT table_schema "Data Base Name", sum( data_length + index_length ) / (1024 * 1024) as Size FROM information_schema.TABLES GROUP BY table_schema;
mysqldump -u [user] -p --all-databases > [dump_name].sql
mysql -D [mydatabase] -o < [dump_name].sql