1.       表占用空间大小计算方法

Select S.SEGMENT_NAME ,DECODE(SUM(BYTES), NULL, 0, SUM(BYTES) / 1024 / 1024) Mbytes  From DBA_SEGMENTS S Where S.SEGMENT_NAME = 'MTL_MATERIAL_TRANSACTIONS' --表名   And S.SEGMENT_TYPE = 'TABLE' Group By S.SEGMENT_NAME

2.       索引占用空间大小计算方法

Select S.SEGMENT_NAME ,DECODE(SUM(BYTES), NULL, 0, SUM(BYTES) / 1024 / 1024) Mbytes  From DBA_SEGMENTS S Where S.SEGMENT_NAME = 'MTL_MATERIAL_TRANSACTIONS_N1' --索引   And S.SEGMENT_TYPE = 'INDEX' Group By S.SEGMENT_NAME

3.       分区表占用空间大小计算方法

Select S.SEGMENT_NAME ,DECODE(SUM(BYTES), NULL, 0, SUM(BYTES) / 1024 / 1024) Mbytes  From DBA_SEGMENTS S Where S.SEGMENT_TYPE = 'TABLE PARTITION' Group By S.SEGMENT_NAME

4.       表空间使用情况

SELECT A.TABLESPACE_NAME 表空间名称,       Round(A.BYTES, 2) "总空间(G)",       Round(B.BYTES, 2) "未用空间(G)",       ROUND(((A.BYTES - B.BYTES) / A.BYTES) * 100, 2) "使用率%"  FROM (SELECT TABLESPACE_NAME, SUM(BYTES) / (1024 * 1024 * 1024) BYTES          FROM DBA_DATA_FILES         GROUP BY TABLESPACE_NAME) A,       (SELECT TABLESPACE_NAME, SUM(BYTES) / (1024 * 1024 * 1024) BYTES          FROM DBA_FREE_SPACE         GROUP BY TABLESPACE_NAME) B WHERE A.TABLESPACE_NAME = B.TABLESPACE_NAME ORDER BY ((A.BYTES - B.BYTES) / A.BYTES) DESC;