mysql数据库查看表占用空间

1.通过information_schema.TABLES来查看每一个表的相信信息，比如：table_rows, avg_row_length, data_length, man_data_length, date_free等数据

字段	含义
Table_catalog	数据表登记目录
Table_schema	数据表所属的数据库名
Table_name	表名称
Table_type	表类型[system view|base table]
Engine	使用的数据库引擎[MyISAM|CSV|InnoDB]
Version	版本，默认值10
Row_format	行格式[Compact|Dynamic|Fixed]
Table_rows	表里所存多少行数据
Avg_row_length	平均行长度
Data_length	数据长度
Max_data_length	最大数据长度
Index_length	索引长度
Data_free	空间碎片
Auto_increment	做自增主键的自动增量当前值
Create_time	表的创建时间
Update_time	表的更新时间
Check_time	表的检查时间
Table_collation	表的字符校验编码集
Checksum	校验和
Create_options	创建选项
Table_comment	表的注释、备注

查看该数据库实例下所有库大小，得到的结果是以MB为单位 

select table_schema,sum(data_length)/1024/1024 as data_length,sum(index_length)/1024/1024 \
as index_length,sum(data_length+index_length)/1024/1024 as sum from information_schema.tables;
+--------------------+---------------+--------------+---------------+
| table_schema       | data_length   | index_length | sum           |
+--------------------+---------------+--------------+---------------+
| information_schema | 2734.92757511 |  86.27539063 | 2821.20296574 |
+--------------------+---------------+--------------+---------------+

查看该实例下各个库大小

select table_schema, sum(data_length+index_length)/1024/1024 as total_mb,
sum(data_length)/1024/1024 as data_mb, sum(index_length)/1024/1024 as index_mb,
count(*) as tables, curdate() as today from information_schema.tables group by table_schema order by 2 desc;
+--------------------+---------------+---------------+-------------+--------+------------+
| table_schema       | total_mb      | data_mb       | index_mb    | tables | today      |
+--------------------+---------------+---------------+-------------+--------+------------+
| data_1234567890    | 2820.59610939 | 2734.39689064 | 86.19921875 |     65 | 2015-11-02 |
| mysql              |    0.60579967 |    0.53744030 |  0.06835938 |     14 | 2015-11-02 |
| information_schema |    0.00781250 |    0.00000000 |  0.00781250 |     35 | 2015-11-02 |   查看单个表状态 show table status from data_1234567890 where name = 'data_1234567890_ss' \G