查询数据库容量大小 - 整个数据库

use information_schema;
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES;

查看所有数据库各容量大小 - 详细

select
table_schema as '数据库',
sum(table_rows) as '记录数',
sum(truncate(data_length/1024/1024, 2)) as '数据容量(MB)',
sum(truncate(index_length/1024/1024, 2)) as '索引容量(MB)'
from information_schema.tables
group by table_schema
order by sum(data_length) desc, sum(index_length) desc;

查看所有数据表各容量大小 - 详细

select
table_schema as '数据库',
table_name as '表名',
table_rows as '记录数',
truncate(data_length/1024/1024, 2) as '数据容量(MB)',
truncate(index_length/1024/1024, 2) as '索引容量(MB)'
from information_schema.tables
order by data_length desc, index_length desc;

查询所有数据表的大小

select * from (select table_schema,TABLE_NAME, concat(truncate(data_length/1024/1024,2),' MB') as data_size,table_rows
from information_schema.tables   ORDER BY  table_rows) t ;

统计每个库大小：

SELECT
table_schema,SUM(AVG_ROW_LENGTH*TABLE_ROWS+INDEX_LENGTH)/1024/1024 AS total_mb
FROM information_schema.TABLES group by table_schema;

统计一下所有库数据量,每张表数据量=AVG_ROW_LENGTH*TABLE_ROWS+INDEX_LENGTH

SELECT
SUM(AVG_ROW_LENGTH*TABLE_ROWS+INDEX_LENGTH)/1024/1024 AS total_mb
FROM information_schema.TABLES

第二种情况：查看指定数据库的大小，比如说：数据库test，方法如下：

use information_schema;
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES where table_schema='[这里修改对应库的名称]';
FROM information_schema.TABLES group by table_schema;

查看指定数据库容量大小 查看mysql库容量大小

select
table_schema as '数据库',
sum(table_rows) as '记录数',
sum(truncate(data_length/1024/1024, 2)) as '数据容量(MB)',
sum(truncate(index_length/1024/1024, 2)) as '索引容量(MB)'
from information_schema.tables
where table_schema='[这里修改对应库的名称]';

查看指定数据库各表容量大小 查看mysql库各表容量大小

select
table_schema as '数据库',
table_name as '表名',
table_rows as '记录数',
truncate(data_length/1024/1024, 2) as '数据容量(MB)',
truncate(index_length/1024/1024, 2) as '索引容量(MB)'
from information_schema.tables
where table_schema='[这里修改对应库的名称]'
order by data_length desc, index_length desc;