如何获取执行计划

1.通过设置变量： autotrace

Set timing on
Set autotrace traceonly
Select * from test;
Set autotrace off

2.分析AWR时，可以根据SQL_ID找到真实的执行计划，绑定变量，统计信息

select hash_value, child_number, sql_text from v$sql s
 where s.SQL_ID = '866n2xzvtyndu';
select * from table(dbms_xplan.display_cursor(hash_value, child_number));

 3.Explain plan for 引发硬解析，但不会执行

explain plan for select * from test;
select * from table(dbms_xplan.display);