甲骨文日期“在...之间"询问 [英] Oracle date "Between" Query

问题描述

我正在使用oracle数据库.我想执行一个查询来检查两个日期之间的数据.

I am using oracle database. i want to execute one query to check the data between two dates.

NAME               START_DATE    
-------------    ------------- 
Small Widget       15-JAN-10 04.25.32.000000 PM      
Product 1          17-JAN-10 04.31.32.000000 PM  



select * from <TABLENAME> where start_date  
BETWEEN '15-JAN-10' AND '17-JAN-10'

但是我没有从上述查询中得到任何结果.我认为我必须使用喜欢"和％".但是我不知道在哪里使用它们.请对此点灯.

But I dont get any results from above query. I think I have to use "like" and "%". But I dont know where to use them. Please throw some lights on this.

提前谢谢.

推荐答案

从输出中判断，您好像已将START_DATE定义为时间戳.如果是正常日期，Oracle将能够处理隐式转换.但不是，您需要将这些字符串显式转换为日期.

Judging from your output it looks like you have defined START_DATE as a timestamp. If it were a regular date Oracle would be able to handle the implicit conversion. But as it isn't you need to explicitly cast those strings to be dates.

SQL> alter session set nls_date_format = 'dd-mon-yyyy hh24:mi:ss'
  2  /

Session altered.

SQL>
SQL> select * from t23
  2  where start_date between '15-JAN-10' and '17-JAN-10'
  3  /

no rows selected

SQL> select * from t23
  2  where start_date between to_date('15-JAN-10') and to_date('17-JAN-10')
  3  /

WIDGET                          START_DATE
------------------------------  ----------------------
Small Widget                    15-JAN-10 04.25.32.000    

SQL> 

但是我们仍然只能得到一行.这是因为START_DATE具有时间元素.如果不指定时间部分，Oracle会将其默认为午夜.对于BETWEEN的 from 端来说是很好的，但对于 until 端来说不是:

But we still only get one row. This is because START_DATE has a time element. If we don't specify the time component Oracle defaults it to midnight. That is fine for the from side of the BETWEEN but not for the until side:

SQL> select * from t23
  2  where start_date between to_date('15-JAN-10') 
  3                       and to_date('17-JAN-10 23:59:59')
  4  /

WIDGET                          START_DATE
------------------------------  ----------------------
Small Widget                    15-JAN-10 04.25.32.000
Product 1                       17-JAN-10 04.31.32.000

SQL>

修改

如果您无法传递时间部分，则有两种选择.一种是更改WHERE子句以从条件中删除时间元素:

If you cannot pass in the time component there are a couple of choices. One is to change the WHERE clause to remove the time element from the criteria:

where trunc(start_date) between to_date('15-JAN-10') 
                            and to_date('17-JAN-10')

这可能会影响性能，因为它在START_DATE取消了所有b树索引的资格.您将需要构建基于函数的索引.

This might have an impact on performance, because it disqualifies any b-tree index on START_DATE. You would need to build a function-based index instead.

或者，您也可以在代码中的日期中添加时间元素:

Alternatively you could add the time element to the date in your code:

where start_date between to_date('15-JAN-10') 
                     and to_date('17-JAN-10') + (86399/86400) 

由于这些问题，许多人更喜欢通过检查日期边界来避免使用between:

Because of these problems many people prefer to avoid the use of between by checking for date boundaries like this:

where start_date >= to_date('15-JAN-10') 
and start_date < to_date('18-JAN-10')

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