ORACLE的分组统计之CUBE(二)

cube统计包含了rollup的统计结果，而且还有其他组合分组结果(小计)，CUBE(n列)，那么分组种类有：

cube分组就是先进行合计(一个不取)，然后小计(到)，最后取标准分组。

与rollup不同，CUBE计算结果和列的顺序无关，如果列顺序不同，默认的结果排序则不同。

SQL> select a.dname,b.job,sum(b.sal) sumsal from scott.dept a,scott.emp b where a.deptno=b.deptno group by cube(a.dname,b.job);

DNAME          JOB           SUMSAL
-------------- --------- ----------
                              29025
               CLERK           4150
               ANALYST         6000
               MANAGER         8275
               SALESMAN        5600
               PRESIDENT       5000
SALES                          9400
SALES          CLERK            950
SALES          MANAGER         2850
SALES          SALESMAN        5600
RESEARCH                      10875

DNAME          JOB           SUMSAL
-------------- --------- ----------
RESEARCH       CLERK           1900
RESEARCH       ANALYST         6000
RESEARCH       MANAGER         2975
ACCOUNTING                     8750
ACCOUNTING     CLERK           1300
ACCOUNTING     MANAGER         2450
ACCOUNTING     PRESIDENT       5000

已选择18行。

执行计划
----------------------------------------------------------
Plan hash value: 2432972551

-------------------------------------------------------------------------------------------
| Id  | Operation                       | Name    | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                |         |    14 |   392 |     5  (20)| 00:00:01 |
|   1 |  SORT GROUP BY                  |         |    14 |   392 |     5  (20)| 00:00:01 |
|   2 |   GENERATE CUBE                 |         |    14 |   392 |     5  (20)| 00:00:01 |
|   3 |    SORT GROUP BY                |         |    14 |   392 |     5  (20)| 00:00:01 |
|   4 |     NESTED LOOPS                |         |    14 |   392 |     4   (0)| 00:00:01 |
|   5 |      TABLE ACCESS FULL          | EMP     |    14 |   210 |     3   (0)| 00:00:01 |
|   6 |      TABLE ACCESS BY INDEX ROWID| DEPT    |     1 |    13 |     1   (0)| 00:00:01 |
|*  7 |       INDEX UNIQUE SCAN         | PK_DEPT |     1 |       |     0   (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   7 - access("A"."DEPTNO"="B"."DEPTNO")

统计信息
----------------------------------------------------------
          0  recursive calls
          0  db block gets
         23  consistent gets
          0  physical reads
          0  redo size
        960  bytes sent via SQL*Net to client
        396  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          2  sorts (memory)
          0  sorts (disk)
         18  rows processed