请问用< 或 > 号会用到索引吗？

[sws_martian]

请问用< 或 > 号会用到索引吗？

select * from tabname where phonenum > '12345';

[kingkingzhu]

会。。。。。

[dawugui]

会...

[kingkingzhu]

<>不会

[Phoenix_99]

不能用索引的情况
1）单行函数nvl,decode.....
2）>,<,>=,<=
3) not..in,exists,is null
4)is null'
所以<,<不用索引

[Phoenix_99]

不过这也得跟具体情况来区别

[kingkingzhu]

scott 下 dept表
SQL> select * from dept where deptno >'30';

DEPTNO DNAME LOC
---------- -------------- -------------
40 OPERATIONS BOSTON
50 ACCOUNTING NEW YORK
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Tim
e |

--------------------------------------------------------------------------------
-------

| 0 | SELECT STATEMENT | | 3 | 60 | 2 (0)| 00:
00:01 |

| 1 | TABLE ACCESS BY INDEX ROWID| DEPT | 3 | 60 | 2 (0)| 00:
00:01 |

|* 2 | INDEX RANGE SCAN | PK_DEPT | 3 | | 1 (0)| 00:
00:01 |

SQL> select * from dept where deptno <> '30';

DEPTNO DNAME LOC
---------- -------------- -------------
50 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
40 OPERATIONS BOSTON

--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 3 | 60 | 3 (0)| 00:00:01 |
|* 1 | TABLE ACCESS FULL| DEPT | 3 | 60 | 3 (0)| 00:00:01 |
--------------------------------------------------------------------------

[huangyunzeng2008]

当然要用了，在oracle中肯定是用个，在其他的不敢保证。