数据库计算每个表所占空间和记录数

sql server

USE database_20160215
GO

SELECT
TableName = obj.name,
TotalRows = prt.rows,
[SpaceUsed(KB)] = SUM(alloc.used_pages)*8
FROM sys.objects obj
JOIN sys.indexes idx on obj.object_id = idx.object_id
JOIN sys.partitions prt on obj.object_id = prt.object_id
JOIN sys.allocation_units alloc on alloc.container_id = prt.partition_id
WHERE
obj.type = 'U' AND idx.index_id IN (0, 1)
GROUP BY obj.name, prt.rows
ORDER BY TableName

Mysql

/*这里面的单位是Byte*/
SELECT
    TABLE_NAME,
    DATA_LENGTH,
    INDEX_LENGTH,
    DATA_LENGTH + INDEX_LENGTH,
    TABLE_ROWS
FROM
    information_schema. TABLES
WHERE
    TABLE_SCHEMA = 'database_20160215';

Oracle

/*查某一用户下的表*/
select SEGMENT_NAME, TABLESPACE_NAME, sum(BYTES) || ' Bytes'
  from USER_extents
 where SEGMENT_TYPE = 'TABLE'
 group by SEGMENT_NAME,
          TABLESPACE_NAME

/*查所有的表*/
select SEGMENT_NAME, TABLESPACE_NAME, sum(BYTES) || ' Bytes'
  from dba_extents
 where SEGMENT_TYPE = 'TABLE'
 group by SEGMENT_NAME, TABLESPACE_NAME