mysql语句查看数据库表所占容量空间大小

一、查看所有数据库容量大小

SELECT
    table_schema AS '数据库',
    sum( table_rows ) AS '记录数',
    sum(
    TRUNCATE ( data_length / 1024 / 1024, 2 )) AS '数据容量(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;

二、查看所有数据库各表容量大小

SELECT
    table_schema AS '数据库',
    table_name AS '表名',
    table_rows AS '记录数',
    TRUNCATE ( data_length / 1024 / 1024, 2 ) AS '数据容量(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;

三、查看指定数据库容量大小

SELECT
    table_schema AS '数据库',
    sum( table_rows ) AS '记录数',
    sum(
    TRUNCATE ( data_length / 1024 / 1024, 2 )) AS '数据容量(MB)',
    sum(
    TRUNCATE ( index_length / 1024 / 1024, 2 )) AS '索引容量(MB)' 
FROM
    information_schema.TABLES 
WHERE
    table_schema = 'osale_im';

四、查看指定数据库各表容量大小

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

五：查看指定数据库指定表容量大小

六. 查看所有产生碎片的表

  SELECT table_schema db, 
         table_name, 
         data_free, 
         engine 
    FROM information_schema.tables 
   WHERE table_schema NOT IN ('information_schema', 'mysql') 
     AND data_free > 0 
ORDER BY DATA_FREE DESC;

查看某个表的碎片大小

SHOW TABLE STATUS LIKE '表名';

查询结果中的'Data_free'字段的值就是碎片大小。

1. 清理表碎片

/*1. MyISAM表*/
 
OPTIMIZE TABLE 表名
 
/*2. InnoDB表*/
 
ALTER TABLE 表名 engine = InnoDB