--------------------------------------------------------------------------------- ...... --使用LEADING Hint scott@TEST>select /*+ leading(t e) */ e.ename,j.job,e.sal,d.deptno 2 from emp e,jobs j,dept d,emp_temp t 3 where e.empno=j.empno 4 and e.deptno=d.deptno 5 and d.loc='CHICAGO' 6 and e.ename=t.ename 7 order by e.ename; 6 rows selected. Execution Plan ---------------------------------------------------------- Plan hash value: 937897748 ---------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ---------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 5 | 270 | 15 (20)| 00:00:01 | | 1 | SORT ORDER BY | | 5 | 270 | 15 (20)| 00:00:01 | |* 2 | HASH JOIN | | 5 | 270 | 14 (15)| 00:00:01 | |* 3 | HASH JOIN | | 5 | 175 | 10 (10)| 00:00:01 | |* 4 | HASH JOIN | | 14 | 336 | 7 (15)| 00:00:01 | | 5 | TABLE ACCESS FULL| EMP_TEMP | 14 | 98 | 3 (0)| 00:00:01 | | 6 | TABLE ACCESS FULL| EMP | 14 | 238 | 3 (0)| 00:00:01 | |* 7 | TABLE ACCESS FULL | DEPT | 1 | 11 | 3 (0)| 00:00:01 | | 8 | TABLE ACCESS FULL | JOBS | 14 | 266 | 3 (0)| 00:00:01 | ---------------------------------------------------------------------------------- ...... --使用Ordered Hint scott@TEST>select /*+ ordered */ e.ename,j.job,e.sal,d.deptno 2 from emp e,jobs j,dept d,emp_temp t 3 where e.empno=j.empno 4 and e.deptno=d.deptno 5 and d.loc='CHICAGO' 6 and e.ename=t.ename 7 order by e.ename; 6 rows selected. Execution Plan ---------------------------------------------------------- Plan hash value: 2459794491 -------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | -------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 5 | 270 | 14 (22)| 00:00:01 | |&nbs |