请问用< 或 > 号会用到索引吗? 请问用< 或 > 号会用到索引吗?select * from tabname where phonenum > '12345'; 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 不能用索引的情况1)单行函数nvl,decode.....2)>,<,>=,<=3) not..in,exists,is null4)is null'所以<,<不用索引 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)| Time |---------------------------------------------------------------------------------------| 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 |-------------------------------------------------------------------------- 当然要用了,在oracle中肯定是用个,在其他的不敢保证。 oracle9i 突然丢失数据 郁闷 急求解决 一个Oracle语句的问题 能够使用其他SQL替代外连接吗?Help。。。。 Imp导入数据时产生错误 郁闷啊!oracle 安装在winxp上的问题 RMAN 恢复数据库失败,求救!在线急等! 请问,在oracle 怎么写sql语句查询dwm数据库以t开头的表啊,谢谢,急 用sql*loader怎样把科学计数法表示的数字导入数据库 个人版ORACLE 在PB中怎样调用 提问:关与授权 MySql存储过程的问题 sql语句,求高手指教
1)单行函数nvl,decode.....
2)>,<,>=,<=
3) not..in,exists,is null
4)is null'
所以<,<不用索引
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 |
--------------------------------------------------------------------------