前言

在开发中我们想知道某个数据库，或者某个数据表的内存大小，那么怎么查询呢？下面通过简单示例一一介绍，希望对您有所帮助。

 某表每行所占字节数

SELECT 
TABLE_NAME , 
CONCAT((DATA_LENGTH + INDEX_LENGTH), ' 字节') AS '每行占用字节数' 
FROM 
information_schema.TABLES 
WHERE 
TABLE_SCHEMA = '你的数据库名' 
AND 
TABLE_TYPE = 'BASE TABLE';

 某个数据库各表所占内存大小

SELECT
	table_schema AS "数据库",
	table_name AS "表名",
	table_rows AS "记录数",
	TRUNCATE ( data_length / 1024 / 1024, 2 ) / 1024 AS "数据容量（GB）",
	TRUNCATE ( index_length / 1024 / 1024, 2 ) / 1024 AS "索引容量（GB）" 
FROM
	information_schema.TABLES 
WHERE
	table_schema = '你的数据库名称' 
ORDER BY
	data_length DESC,
	index_length DESC;