查看执行计划的几种方法

1、使用第三方工具

plsal dev的F5，且执行计划可以在首选项中设置，如下图所示：

2、在SQL*PLUS命令窗口或者PL/SQL的命令窗口下执行下面语句：

SQL> EXPLAIN PLAN FOR
  2  select /*+rowid(o)*/* from t_objects o where rowid <= 'AAAS0NAAEAAAwFbAAR' and object_id =100;
 
Explained
 
SQL> SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY);
 
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 3283999821
--------------------------------------------------------------------------------
| Id  | Operation                   | Name      | Rows  | Bytes | Cost (%CPU)| T
--------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |           |    43 |  9417 |   300   (1)| 0
|*  1 |  TABLE ACCESS BY ROWID RANGE| T_OBJECTS |    43 |  9417 |   300   (1)| 0
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
   1 - access(ROWID<='AAAS0NAAEAAAwFbAAR')
       filter("OBJECT_ID"=100)
Note
-----
   - dynamic sampling used for this statement (level=2)
 
18 rows selected

3、在sqlplus窗口执行以下命令：

set autotrace on