A>create table t
  2  as
  3  select rownum id1,dbms_random.random id2,rpad('*',200,'*') data
  4  from all_objects;

Table created.

A>create index organized on t(id1);

Index created.

A>create index disorganized on t(id2);

Index created.

A>select index_name, clustering_factor from user_indexes where table_name = 'T';

INDEX_NAME           CLUSTERING_FACTOR
-------------------- -----------------
DISORGANIZED                     57643
ORGANIZED                         1748

--id1列有序，所以CLUF小接近块数；相反id2列随机无序，所以CLUF大接近行数

A>exec dbms_stats.gather_table_stats( user, 'T' );

PL/SQL procedure successfully completed.

select num_rows, blocks from user_tables where table_name = 'T';

  NUM_ROWS     BLOCKS
---------- ----------
     57670       1784

--下面是重点
--它表明：一般情况下，从物理存储上看的话，一个表只可能按照一个列有序存放
--举个例子，甲乙两人综合素质相当，但在具体领域又各有千秋，在音乐上甲胜乙，所以甲>乙；在绘画上乙胜甲，所以乙>甲

A>A>create table t2 as select * from t order by id2;

Table created.

A>create index id1_idx on t2(id1);

Index created.

A>A>create index id2_idx on t2(id2);

Index created.

A>select index_name, clustering_factor from user_indexes where table_name = 'T2';

INDEX_NAME           CLUSTERING_FACTOR
-------------------- -----------------
ID2_IDX                           1748
ID1_IDX                          57642

--原来按id1列有序，现在按照id2列排序，Id1列自然变成随机，所以体现在CLUF上，是id2列的CLUF变小了

参考：https://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1032431852141