MySQL查看数据库、表占用磁盘大小

直接复制执行

1、查询所有数据库占用磁盘空间大小

select
TABLE_SCHEMA,
concat(truncate(sum(data_length)/1024/1024,2),' MB') as data_size,
concat(truncate(sum(index_length)/1024/1024,2),'MB') as index_size
from information_schema.tables
group by TABLE_SCHEMA
ORDER BY data_size desc;

select concat(truncate(sum(data_length)/1024/1024,2),'MB') as data_size,
         concat(truncate(sum(max_data_length)/1024/1024,2),'MB') as max_data_size,
         concat(truncate(sum(data_free)/1024/1024,2),'MB') as data_free,
         concat(truncate(sum(index_length)/1024/1024,2),'MB') as index_size
  from information_schema.tables
where TABLE_SCHEMA = 'databasename'; # databasename 具体库名

2、查询单个库中所有表磁盘占用大小

select concat(truncate(sum(data_length)/1024/1024,2),'MB') as data_size,
         concat(truncate(sum(max_data_length)/1024/1024,2),'MB') as max_data_size,
         concat(truncate(sum(data_free)/1024/1024,2),'MB') as data_free,
         concat(truncate(sum(index_length)/1024/1024,2),'MB') as index_size
  from information_schema.tables
where TABLE_NAME = 'tablename'; # tablename 具体表名

-- 查看数据库中所有表的信息
SELECT
    concat( table_schema, '.', table_name ) AS 'Table Name',
    table_rows AS 'Number of Rows',
    concat( round( data_length / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Data Size',
    concat( round( index_length / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Index Size',
    concat( round( ( data_length + index_length ) / ( 1024 * 1024 * 1024 ), 6 ), ' G' ) AS 'Total' 
FROM
    information_schema.TABLES W 
WHERE
    table_schema LIKE 'database name';

3、查看表空间

# 单位GB
SELECT concat( round( sum( data_length ) / ( 1024 * 1024 * 1024 ), 6 ), 'GB' ) AS 'Total Data Size' 
FROM information_schema.TABLES 
WHERE table_schema LIKE 'database name';

4、查看索引空间

SELECT CONCAT( ROUND( SUM( index_length ) / ( 1024 * 1024 * 1024 ), 6 ), ' GB' ) AS 'Total Index Size' 
FROM information_schema.TABLES 
WHERE table_schema LIKE 'dabatase name';

5、使用optimize命令

optimize table tb_report_inventory;

使用的时间比较长，需要耐心等待。

注意：optimize执行时会将表锁住，所以不要在高峰期使用。也不要经常使用，每月一次就足够了

问题

若执行 2、查询单个库中所有表磁盘占用大小出现以下报错：

Expression #2 of SELECT list is not in GROUP BY clause and contains
nonaggregated column ‘sss.month_id’ which is not functionally
dependent on columns in GROUP BY clause; this is incompatible with
sql_mode=only_full_group_by

解决方法一：
此方法只是临时解决，重启mysql服务器会还原。

打开navcat，

用sql查询：

select @@global.sql_mode

查询出来的值为：

ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

去掉ONLY_FULL_GROUP_BY，重新设置值。

set @@global.sql_mode
=’STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION’;

解决方法二：

成功的步骤：

打开文件

sudo vim /etc/mysql/conf.d/mysql.cnf

滚动到文件底部复制并粘贴

[mysqld]
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

到文件的底部

保存并退出输入模式

sudo service mysql restart

重启MySQL。
完成！