SQL> insert into t values(1,'a') ;
已创建 1 行。
SQL> insert into t values(2,'a') ;
已创建 1 行。
SQL> insert into t values(3,'a') ;
已创建 1 行。
SQL> insert into t values(4,'a') ;
已创建 1 行。
SQL> commit ;
提交完成。
SQL> set autot traceonly exp ;
SP2-0613: 无法验证 PLAN_TABLE 格式或实体
SP2-0611: 启用EXPLAIN报告时出错
SQL> @?/rdbms/admin/utlxplan
表已创建。
SQL> set autot traceonly exp ;
SQL> select * from t ;
Execution Plan
----------------------------------------------------------
0SELECT STATEMENT Optimizer=CHOOSE
10 TABLE ACCESS (FULL) OF 'T'
SQL> select /*+index(t t_id)*/* from t ;
Execution Plan
----------------------------------------------------------
0SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=82 Bytes=5330
)
10 TABLE ACCESS (FULL) OF 'T' (Cost=2 Card=82 Bytes=5330)
SQL> select /*+index(t t_id)*/* from t where id =1;
Execution Plan
----------------------------------------------------------
0SELECT STATEMENT Optimizer=CHOOSE (Cost=1 Card=1 Bytes=65)
10 TABLE ACCESS (BY INDEX ROWID) OF 'T' (Cost=1 Card=1 Bytes=
65)
21 INDEX (RANGE SCAN) OF 'T_ID' (NON-UNIQUE) (Cost=1 Card=1
)
SQL> select /*+index(t t_id)*/* from t ;
Execution Plan
----------------------------------------------------------
0SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=82 Bytes=5330
)
10 TABLE ACCESS (FULL) OF 'T' (Cost=2 Card=82 Bytes=5330)
