010.mysql-mysql查询表注释、字段、备注

第二种：查询所有数据的大小
select concat(round(sum(DATA_LENGTH/1024/1024),2),‘MB‘) as data from information_schema.TABLES
第三种：查看指定数据库的大小，比如说：数据库apoyl
select concat(round(sum(DATA_LENGTH/1024/1024),2),‘MB‘) as data from information_schema.TABLES where table_schema=‘apoyl‘;
第四种：查看指定数据库的表的大小，比如说：数据库apoyl 中apoyl_test表
select concat(round(sum(DATA_LENGTH/1024/1024),2),‘MB‘) as data from information_schema.TABLES where table_schema=‘apoyl‘ and table_name=‘apoyl_test‘;

库的每个scheme
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


库的所有
select 
 sum(记录数)
,sum(`数据容量(MB)`)
,sum(`索引容量(MB)`)
from 
(

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

)b;