第一種情況：
查詢所有數據庫的總大小
，方法如下：
mysql> use information_schema;
mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES;
+-----------+
| data |
+-----------+
| 3052.76MB |
+-----------+
1 row in set (0.02 sec)
統計一下所有庫數據量
每張表數據量=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
統計每個庫大小：
SELECT
table_schema,SUM(AVG_ROW_LENGTH*TABLE_ROWS+INDEX_LENGTH)/1024/1024 AS total_mb
FROM information_schema.TABLES group by table_schema;
第二種情況：
查看指定數據庫的大小
，比如說：數據庫test，方法如下：
mysql> use information_schema;
mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES where table_schema='
test
';
+----------+
| data |
+----------+
| 142.84MB |
+----------+
1 row in set (0.00 sec)
1.查看所有數據庫各容量大小
select
table_schema as '數據庫',
sum(table_rows) as '記錄數',
sum(truncate(data_length/1024/1024, 2)) as '數據容量(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.查看所有數據庫各表容量大小
select
table_schema as '數據庫',
table_name as '表名',
table_rows as '記錄數',
truncate(data_length/1024/1024, 2) as '數據容量(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.查看指定數據庫容量大小
例：查看mysql庫容量大小
select
table_schema as '數據庫',
sum(table_rows) as '記錄數',
sum(truncate(data_length/1024/1024, 2)) as '數據容量(MB)',
sum(truncate(index_length/1024/1024, 2)) as '索引容量(MB)'
from information_schema.tables
where table_schema='mysql';
4.查看指定數據庫各表容量大小
例：查看mysql庫各表容量大小
select
table_schema as '數據庫',
table_name as '表名',
table_rows as '記錄數',
truncate(data_length/1024/1024, 2) as '數據容量(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;