查看SQL执行计划

1、explain plan for

SQL> select * from table(dbms_xplan.display());

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------

Plan hash value: 1388734953

-----------------------------------------------------------------

| Id | Operation | Name | Rows | Cost (%CPU)| Time |

-----------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 2 (0)| 00:00:01 |

| 1 | FAST DUAL | | 1 | 2 (0)| 00:00:01 |

-----------------------------------------------------------------

已选择8行。

2、set autotrace on

SQL> set autotrace on

SQL> select sysdate from dual;

SYSDATE

-------------------

2014-02-25 20:01:03

执行计划

----------------------------------------------------------

Plan hash value: 1388734953

-----------------------------------------------------------------

| Id | Operation | Name | Rows | Cost (%CPU)| Time |

-----------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 2 (0)| 00:00:01 |

| 1 | FAST DUAL | | 1 | 2 (0)| 00:00:01 |

-----------------------------------------------------------------

统计信息

----------------------------------------------------------

1 recursive calls

0 db block gets

0 consistent gets

0 physical reads

0 redo size

412 bytes sent via SQL*Net to client

385 bytes received via SQL*Net from client

2 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

1 rows processed

3、使用工具查看sql执行计划。