用explain plan查看执行计划

1.创建PLAN_TABLE表

SQL> conn b2c20/b2c20
Connected.
SQL> @?/rdbms/admin/utlxplan.sql
 
Table created.

2.运行EXPLAIN PLAN

SQL> explain plan for
  2  select count(*) from bc_customer;
 
Explained.

3.查看EXPLAIN PLAN

SQL> @?/rdbms/admin/utlxpls
 
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
 
---------------------------------------------------------------------
| Id  | Operation            |  Name        | Rows  | Bytes | Cost  |
---------------------------------------------------------------------
|   0 | SELECT STATEMENT     |              |       |       |       |
|   1 |  SORT AGGREGATE      |              |       |       |       |
|   2 |   TABLE ACCESS FULL  | BC_CUSTOMER  |       |       |       |
---------------------------------------------------------------------
 
Note: rule based optimization
 
10 rows selected.

显然，这种方法查看执行计划比较麻烦。