Oracle 数据库对象增长记录查询对比语句 - 数据库编程

select * from (
select a.owner,a.segment_name,a.tablespace_name,b.megas-a.megas diff
from
(select owner,segment_name,tablespace_name,sum(megas) megas
from object_rd
where to_char(recode_time,'yyyymmdd')='20111230'
group by owner,segment_name,tablespace_name)a,
(select owner,segment_name,tablespace_name,sum(megas) megas
from object_rd

where to_char(recode_time,'yyyymmdd')='20111231'
group by owner,segment_name,tablespace_name)b
where a.owner=b.owner
and a.segment_name=b.segment_name
--and a.segment_type=b.segment_type
and a.tablespace_name=b.tablespace_name)c
where c.diff>1
order by c.diff desc