schemata表：这个表里面主要是存储在Mysql中的所有的数据库的信息

　　tables表：这个表里存储了所有数据库中的表的信息，包括每个表有多少个列等信息。

　　columns表：这个表存储了所有表中的表字段信息。

　　statistics表：存储了表中索引的信息。

　　user_privileges表：存储了用户的权限信息。

　　schema_privileges表：存储了数据库权限。

　　table_privileges表：存储了表的权限。

　　column_privileges表：存储了列的权限信息。

　　character_sets表：存储了mysql可以用的字符集的信息。

　　collations表：提供各个字符集的对照信息。

　　collation_character_set_applicability表：相当于collations表和character_sets表的前两个字段的一个对比，记录了字符集之间的对照信息。

　　table_constraints表：这个表主要是用于记录表的描述存在约束的表和约束类型。

　　key_column_usage表：记录具有约束的列。

　　routines表：记录了存储过程和函数的信息，不包含自定义的过程或函数信息。

　　views表：记录了视图信息，需要有show view权限。

　　triggers表：存储了触发器的信息，需要有super权限。

Mysql查看数据库表容量大小

1.查看所有数据库容量大小

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
 
group by table_schema
 
order by sum(data_length) desc, sum(index_length) desc

2.查看所有数据库各表容量大小

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
 
order by data_length desc, index_length desc;

3.查看指定数据库容量大小

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="mysql"

4.查看指定数据库各表容量大小

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="mysql"
 
order by data_length desc, index_length desc;

Mysql查看数据库,表占用磁盘大小

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;

2、查询单个库中所有表磁盘占用大小

select 
TABLE_NAME, 
concat(truncate(data_length/1024/1024,2)," MB") as data_size,
concat(truncate(index_length/1024/1024,2)," MB") as index_size
from information_schema.tables 
where TABLE_SCHEMA = "查询的表名"
group by TABLE_NAME
order by data_length desc;

 

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