mysql のコマンドで、テーブルの定義や細かいステータスは見れますが、ふと収容先の全データベースのサイズを見る必要があったので、自作してます。
名前は、コマンド用なので短くして、引数なしにしてます。

[ DDL ]

CREATE DEFINER=`root`@`localhost` PROCEDURE `dbsize`()
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT '簡単データベースサイズ'
BEGIN

SELECT 
    table_schema,
    sum(data_length) /1024/1024 + sum(index_length) /1024/1024 AS total_mb,
    sum(data_length) /1024/1024 AS data_mb,
    sum(index_length) /1024/1024 AS index_mb
FROM 
    information_schema.tables  
GROUP BY 
    table_schema 
ORDER BY       
    sum(data_length + index_length) DESC;

END

[ 利用例 ]

mysql> call dbsize;
+--------------------+---------------+---------------+---------------+
| table_schema       | total_mb      | data_mb       | index_mb      |
+--------------------+---------------+---------------+---------------+
| ??????????         | 4028.40940857 | 2589.96604919 | 1438.44335938 |
| ??????????         | 3389.75976753 | 2149.07226753 | 1240.68750000 |
| ??????????         | 1720.67187500 |  812.59375000 |  908.07812500 |
| mysql              |   11.26994324 |   10.99552917 |    0.27441406 |
| ??????             |    3.45312500 |    2.07812500 |    1.37500000 |
| information_schema |    0.15625000 |    0.15625000 |    0.00000000 |
| sys                |    0.01562500 |    0.01562500 |    0.00000000 |
| performance_schema |    0.00000000 |    0.00000000 |    0.00000000 |
+--------------------+---------------+---------------+---------------+
19 rows in set (0.27 sec)

Query OK, 0 rows affected (0.27 sec)