Oracle查看SQL语句的执行计划

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一、explain plan for 方法

SQL> explain plan for select * from dept;Explained.SQL> select * from TABLE(dbms_xplan.display);PLAN_TABLE_OUTPUT--------------------------------------------------------------------------------Plan hash value: 3383998547--------------------------------------------------------------------------| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |--------------------------------------------------------------------------|   0 | SELECT STATEMENT  |      |     4 |    80 |     3   (0)| 00:00:01 ||   1 |  TABLE ACCESS FULL| DEPT |     4 |    80 |     3   (0)| 00:00:01 |--------------------------------------------------------------------------8 rows selected.SQL>

二、set autotrace 方法

SQL> set autotrace traceonly explain;SQL> select * from dept;Execution Plan----------------------------------------------------------Plan hash value: 3383998547--------------------------------------------------------------------------| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |--------------------------------------------------------------------------|   0 | SELECT STATEMENT  |      |     4 |    80 |     3   (0)| 00:00:01 ||   1 |  TABLE ACCESS FULL| DEPT |     4 |    80 |     3   (0)| 00:00:01 |--------------------------------------------------------------------------SQL>

关于set autotrace有几种使用方法

(1)set autotrace off             ------- 不生成autotrace 报告，这是缺省模式(2)set autotrace on explain      ------- 包含执行计划、查询结果(3)set autotrace on statistics   ------- 只包含统计信息、查询结果(4)set autotrace on  ------- 包含执行计划、统计信息、查询结果(5)set autotrace traceonly       ------- 包含执行计划、统计信息(6)set autotrace traceonly explain;  -------只包含执行计划

三、

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