MySQL的 information_schema 數(shù)據(jù)庫，保存著數(shù)據(jù)庫的容量和使用信息?？刹樵償?shù)據(jù)庫中每個(gè)表占用的空間、表記錄的行數(shù)。

Tables表的結(jié)構(gòu)

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;

• 主要字段說明

TABLE_SCHEMA : 數(shù)據(jù)庫名
TABLE_NAME：表名
ENGINE：所使用的存儲引擎
TABLE_ROWS：記錄數(shù)
DATA_LENGTH：數(shù)據(jù)大小
INDEX_LENGTH：索引大小

• 實(shí)例

• 查詢指定數(shù)據(jù)庫的所有表名稱，行數(shù)

USE information_schema;

SELECT TABLE_NAME,table_rows FROM TABLES WHERE TABLE_SCHEMA = '數(shù)據(jù)庫名字' ORDER BY table_rows DESC;

• 查詢指定庫的數(shù)據(jù)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  =  '數(shù)據(jù)庫名字';