请问有大神知道为何这两个查询剩余表空间的sql查出来的结果会有较大差异?
一个是用SYS.SM$TS_AVAIL、SYS.SM$TS_USED、SYS.SM$TS_FREE查询的
SELECT A.TABLESPACE_NAME,A.BYTES/1024/1024 TOTAL,
B.BYTES/1024/1024 USED, C.BYTES/1024/1024 FREE,
(B.BYTES*100)/A.BYTES "% USED",
(C.BYTES*100)/A.BYTES "% FREE"
FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE C
WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME
AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;
另一个是用DBA_FREE_SPACE查询的
SELECT TABLESPACE_NAME "表空间",
To_char(Round(BYTES / 1024, 2), '99990.00')
|| '' "实有",
To_char(Round(FREE / 1024, 2), '99990.00')
|| 'G' "现有",
To_char(Round(( BYTES - FREE ) / 1024, 2), '99990.00')
|| 'G' "使用",
To_char(Round(10000 * USED / BYTES) / 100, '99990.00')
|| '%' "比例"
FROM (SELECT A.TABLESPACE_NAME TABLESPACE_NAME,
Floor(A.BYTES / ( 1024 * 1024 )) BYTES,
Floor(B.FREE / ( 1024 * 1024 )) FREE,
Floor(( A.BYTES - B.FREE ) / ( 1024 * 1024 )) USED
FROM (SELECT TABLESPACE_NAME TABLESPACE_NAME,
Sum(BYTES) BYTES
FROM DBA_DATA_FILES
GROUP BY TABLESPACE_NAME) A,
(SELECT TABLESPACE_NAME TABLESPACE_NAME,
Sum(BYTES) FREE
FROM DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME) B
WHERE A.TABLESPACE_NAME = B.TABLESPACE_NAME)
--WHERE TABLESPACE_NAME LIKE 'CDR%' --这一句用于指定表空间名称
ORDER BY Floor(10000 * USED / BYTES) DESC;
恳盼大神们的回复,谢谢!