说明

• TABLE_NAME ：表名字；
• DATA_LENGTH ： 数据大小；
• INDEX_LENGTH ：索引大小；
• TABLE_ROWS ： 记录数量；
• TABLE_SCHEMA ： 数据库名字；
• ENGINE：所使用的存储引擎；

information_schema ：
是mysql自带的，它提供了访问数据库元数据的方式，元数据是关于数据的数据，
如数据库名或表名，列的数据类型，或访问权限等。

有些时候用于表述该信息的其他术语包括“数据词典”和“系统目录”。

一个表占用空间的大小，相当于是 数据大小 + 索引大小；

SELECT
	TABLE_NAME,
	DATA_LENGTH,
	INDEX_LENGTH,
	(DATA_LENGTH + INDEX_LENGTH) AS length,
	TABLE_ROWS,
	concat(
		round(
			(DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024,
			3
		),
		'MB'
	) AS total_size
FROM
	information_schema. TABLES
WHERE
	TABLE_SCHEMA = 'database_name'
ORDER BY
	length DESC;

mysql> SELECT TABLE_NAME,DATA_LENGTH,INDEX_LENGTH,(DATA_LENGTH+INDEX_LENGTH) as length,TABLE_ROWS,concat(round((DATA_LENGTH+INDEX_LENGTH)/1024/1024,3), 'MB') as total_size FROM information_schema.TABLES WHERE TABLE_SCHEMA='text' order by length desc;
+------------------------------+-------------+--------------+--------+------------+------------+
| TABLE_NAME                   | DATA_LENGTH | INDEX_LENGTH | length | TABLE_ROWS | total_size |
+------------------------------+-------------+--------------+--------+------------+------------+
| new_comments                 |       16384 |        81920 |  98304 |          6 | 0.094MB    |
| admin_operation_log          |       81920 |        16384 |  98304 |        195 | 0.094MB    |
| admin_permissions            |       16384 |        16384 |  32768 |          6 | 0.031MB    |
| system_attribute             |       16384 |        16384 |  32768 |          0 | 0.031MB    |
| cate                         |       16384 |        16384 |  32768 |         18 | 0.031MB    |
| product_sku                  |       16384 |        16384 |  32768 |          0 | 0.031MB    |
| admin_users                  |       16384 |        16384 |  32768 |          0 | 0.031MB    |
| product_attribute_option     |       16384 |        16384 |  32768 |          2 | 0.031MB    |
| admin_roles                  |       16384 |        16384 |  32768 |          0 | 0.031MB    |
| product_attribute_and_option |       16384 |        16384 |  32768 |          0 | 0.031MB    |
| product_attribute            |       16384 |        16384 |  32768 |          2 | 0.031MB    |
| users                        |       16384 |            0 |  16384 |          0 | 0.016MB    |
| orders                       |       16384 |            0 |  16384 |          5 | 0.016MB    |
| admin_permission_menu        |       16384 |            0 |  16384 |          0 | 0.016MB    |
| tb_score                     |       16384 |            0 |  16384 |         10 | 0.016MB    |
| migrations                   |       16384 |            0 |  16384 |          4 | 0.016MB    |
| likecate                     |       16384 |            0 |  16384 |          6 | 0.016MB    |
| admin_menu                   |       16384 |            0 |  16384 |         12 | 0.016MB    |
| sign_in_reward               |       16384 |            0 |  16384 |          7 | 0.016MB    |
| deepcate                     |       16384 |            0 |  16384 |         11 | 0.016MB    |
| sign_in                      |       16384 |            0 |  16384 |          4 | 0.016MB    |
| admin_role_users             |       16384 |            0 |  16384 |          0 | 0.016MB    |
| admin_role_permissions       |       16384 |            0 |  16384 |          0 | 0.016MB    |
| product                      |       16384 |            0 |  16384 |          0 | 0.016MB    |
| admin_role_menu              |       16384 |            0 |  16384 |          0 | 0.016MB    |
| password_resets              |       16384 |            0 |  16384 |          0 | 0.016MB    |
+------------------------------+-------------+--------------+--------+------------+------------+
26 rows in set (0.00 sec)

mysql>