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SQL>set autotrace onSQL>select sal from emp where empno=7902;
SAL
----------
3000
Execution Plan
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Plan hash value: 2949544139
--------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 8 | 1 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| EMP | 1 | 8 | 1 (0)| 00:00:01 |
|* 2 | INDEX UNIQUE SCAN | PK_EMP | 1 | | 0 (0)| 00:00:01 |
--------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
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2 - access("EMPNO"=7902)
【测试】并使用scott用户下的emp表写一条SQL语句，执行计划走唯一索引
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原文地址：http://www.cnblogs.com/tomatoes-/p/5970969.html
