如何查看执行计划的优劣，请教各位大哥大姐了！！！！！

Question

第一份：MEMBERINFO作为驱动表，2个表都走索引
------------------| Id  | Operation                       | Name           | Rows  | Bytes | Cost
(%CPU)| Time     |--------------------------------------------------------------------------------
------------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                |                |   591 | 97515 |   212
K  (1)| 00:42:31 ||*  1 |  HASH JOIN                      |                |   591 | 97515 |   212
K  (1)| 00:42:31 ||   2 |   TABLE ACCESS BY INDEX ROWID   | MEMBERINFO     | 13080 |   613K|  9357
   (1)| 00:01:53 ||   3 |    INDEX FULL SCAN              | MEMBERINFOPKID | 13080 |       |    34
   (0)| 00:00:01 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------|   4 |   VIEW                          |                |   617 | 72189 |   203
K  (1)| 00:40:38 ||   5 |    HASH GROUP BY                |                |   617 | 27765 |   203
K  (1)| 00:40:38 ||*  6 |     FILTER                      |                |       |       |
      |          ||*  7 |      TABLE ACCESS BY INDEX ROWID| PBETDETAIL     |   352K|    15M|   203PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
K  (1)| 00:40:38 ||*  8 |       INDEX RANGE SCAN          | BETTIME        |   352K|       |  1283
   (1)| 00:00:16 |--------------------------------------------------------------------------------
------------------
Predicate Information (identified by operation id):
---------------------------------------------------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------第二份
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                |                |   591 | 97515 |   203
K  (1)| 00:40:46 ||   1 |  NESTED LOOPS                   |                |   591 | 97515 |   203
K  (1)| 00:40:46 ||   2 |   VIEW                          |                |   617 | 72189 |   203
K  (1)| 00:40:38 ||   3 |    HASH GROUP BY                |                |   617 | 27765 |   203
K  (1)| 00:40:38 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------|*  4 |     FILTER                      |                |       |       |
      |          ||*  5 |      TABLE ACCESS BY INDEX ROWID| PBETDETAIL     |   352K|    15M|   203
K  (1)| 00:40:38 ||*  6 |       INDEX RANGE SCAN          | BETTIME        |   352K|       |  1283
   (1)| 00:00:16 ||   7 |   TABLE ACCESS BY INDEX ROWID   | MEMBERINFO     |     1 |    48 |     1PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
   (0)| 00:00:01 ||*  8 |    INDEX UNIQUE SCAN            | MEMBERINFOPKID |     1 |       |     0
   (0)| 00:00:01 |--------------------------------------------------------------------------------
------------------
Predicate Information (identified by operation id):
---------------------------------------------------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
第三份：不走索引，执行全表扫描
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |            |   591 | 97515 | 47304   (2)| 00:09:
28 ||*  1 |  HASH JOIN            |            |   591 | 97515 | 47304   (2)| 00:09:
28 ||   2 |   VIEW                |            |   617 | 72189 | 47191   (2)| 00:09:
27 ||   3 |    HASH GROUP BY      |            |   617 | 27765 | 47191   (2)| 00:09:
27 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------|*  4 |     FILTER            |            |       |       |            |
   ||*  5 |      TABLE ACCESS FULL| PBETDETAIL |   352K|    15M| 47156   (2)| 00:09:
26 ||   6 |   TABLE ACCESS FULL   | MEMBERINFO | 13080 |   613K|   112   (2)| 00:00:
02 |--------------------------------------------------------------------------------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------第一份第二份走索引，第3份是全表扫描，PBETDETAIL 表中的数据有400多W，MEMBERINFO 只有1W多点

Answer 1

第3份计划的执行时间Elapsed: 00:00:03.46
第2份计划执行的时间Elapsed: 00:00:01.75
第1份计划执行的时间Elapsed: 00:00:01.37| Id | Operation | Name | Rows | Bytes | Cost(%CPU)| Time |
还有请教大家Cost(%CPU)表示什么意思，还有ID，是不是最大的最开始执行呢，Bytes 是不是要读取多少内容的大小，那个时间是代表的什么时间？？？从执行的时间上面看，第一份无疑是最好的，但是我想请教大家的是这3份计划的那一种方式比较合适呢

Answer 2

http://blog.csdn.net/tianlesoftware/article/details/5827245