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mysql查询库大小,表行数,索引大小

MySQL的 information_schema 数据库,保存着数据库的容量和使用信息。可查询数据库中每个表占用的空间、表记录的行数。

Tables表的结构

CREATE TEMPORARY TABLE `TABLES` (
  `TABLE_CATALOG` varchar(512) NOT NULL DEFAULT '',
  `TABLE_SCHEMA` varchar(64) NOT NULL DEFAULT '',
  `TABLE_NAME` varchar(64) NOT NULL DEFAULT '',
  `TABLE_TYPE` varchar(64) NOT NULL DEFAULT '',
  `ENGINE` varchar(64) DEFAULT NULL,
  `VERSION` bigint(21) unsigned DEFAULT NULL,
  `ROW_FORMAT` varchar(20) DEFAULT NULL,
  `TABLE_ROWS` bigint(21) unsigned DEFAULT NULL,
  `AVG_ROW_LENGTH` bigint(21) unsigned DEFAULT NULL,
  `DATA_LENGTH` bigint(21) unsigned DEFAULT NULL,
  `MAX_DATA_LENGTH` bigint(21) unsigned DEFAULT NULL,
  `INDEX_LENGTH` bigint(21) unsigned DEFAULT NULL,
  `DATA_FREE` bigint(21) unsigned DEFAULT NULL,
  `AUTO_INCREMENT` bigint(21) unsigned DEFAULT NULL,
  `CREATE_TIME` datetime DEFAULT NULL,
  `UPDATE_TIME` datetime DEFAULT NULL,
  `CHECK_TIME` datetime DEFAULT NULL,
  `TABLE_COLLATION` varchar(32) DEFAULT NULL,
  `CHECKSUM` bigint(21) unsigned DEFAULT NULL,
  `CREATE_OPTIONS` varchar(255) DEFAULT NULL,
  `TABLE_COMMENT` varchar(2048) NOT NULL DEFAULT ''
) ENGINE=MEMORY DEFAULT CHARSET=utf8;

  • 主要字段说明
TABLE_SCHEMA : 数据库名
TABLE_NAME:表名
ENGINE:所使用的存储引擎
TABLE_ROWS:记录数
DATA_LENGTH:数据大小
INDEX_LENGTH:索引大小
  • 实例

  • 查询指定数据库的所有表名称,行数

USE information_schema;

SELECT TABLE_NAME,table_rows FROM TABLES WHERE TABLE_SCHEMA = '数据库名字' ORDER BY table_rows DESC;
  • 查询指定库的数据大小,索引大小
SELECT CONCAT(ROUND(SUM(DATA_LENGTH/1024/1024),2),'MB') AS total_data_size, CONCAT(ROUND(SUM(index_length)/(1024*1024), 2), ' MB') AS total_index_size FROM TABLES  WHERE table_schema  =  '数据库名字';