SELECT 
    table_name AS "Table",  
    round(((data_length + index_length) / 1024 / 1024), 2) as size   
FROM information_schema.TABLES  
WHERE table_schema = "YOUR_DATABASE_NAME"  
ORDER BY size DESC; 

这将对大小进行排序(DB大小以MB为单位)。

这只是一个供以后参考的说明。所有答案都依赖于I_S.TABLES。例如，如果你在表中有blob字段，它不会告诉你正确的大小。LOB页存储在外部页中，因此不计入聚集索引。 事实上有一个注释:

对于NDB表，该语句的输出显示适当的值 AVG_ROW_LENGTH和DATA_LENGTH列，例外 没有考虑到BLOB列。

我发现InnoDB也是如此。

我已经创建了社区Bug相同。

Size of all tables: Suppose your database or TABLE_SCHEMA name is "news_alert". Then this query will show the size of all tables in the database. SELECT TABLE_NAME AS `Table`, ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024),2) AS `Size (MB)` FROM information_schema.TABLES WHERE TABLE_SCHEMA = "news_alert" ORDER BY (DATA_LENGTH + INDEX_LENGTH) DESC; Output: +---------+-----------+ | Table | Size (MB) | +---------+-----------+ | news | 0.08 | | keyword | 0.02 | +---------+-----------+ 2 rows in set (0.00 sec) For the specific table: Suppose your TABLE_NAME is "news". Then SQL query will be- SELECT TABLE_NAME AS `Table`, ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024),2) AS `Size (MB)` FROM information_schema.TABLES WHERE TABLE_SCHEMA = "news_alert" AND TABLE_NAME = "news" ORDER BY (DATA_LENGTH + INDEX_LENGTH) DESC; Output: +-------+-----------+ | Table | Size (MB) | +-------+-----------+ | news | 0.08 | +-------+-----------+ 1 row in set (0.00 sec)

这应该在mysql中测试，而不是postgresql:

SELECT table_schema, # "DB Name", 
Round(Sum(data_length + index_length) / 1024 / 1024, 1) # "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

如果你有ssh访问权限，你可能想简单地尝试du -hc /var/lib/mysql(或不同的datadir，在my.cnf中设置)。

SELECT TABLE_NAME AS table_name, 
table_rows AS QuantofRows, 
ROUND((data_length + index_length) /1024, 2 ) AS total_size_kb 
FROM information_schema.TABLES
WHERE information_schema.TABLES.table_schema = 'db'
ORDER BY (data_length + index_length) DESC; 

以上2个都是在mysql上测试的