Oracle DateTime在哪里子句? [英] Oracle DateTime in Where Clause?

问题描述

我有类似这样的sql:

I have sql something like this:

SELECT EMP_NAME, DEPT
FROM EMPLOYEE
WHERE TIME_CREATED >= TO_DATE('26/JAN/2011','dd/mon/yyyy')

->这将返回10行，并且TIME_CREATED = '26 -JAN-2011'

-> This returns 10 rows and TIME_CREATED = '26-JAN-2011'

现在，当我这样做时，我什么也没回来，

Now when i do this i don't get any rows back,

SELECT EMP_NAME, DEPT
    FROM EMPLOYEE
    WHERE TIME_CREATED = TO_DATE('26/JAN/2011','dd/mon/yyyy')

->采取大于大于采取的措施

-> Took the greater than out

任何理由吗?

推荐答案

是:TIME_CREATED包含日期和时间.使用TRUNC删除时间:

Yes: TIME_CREATED contains a date and a time. Use TRUNC to strip the time:

SELECT EMP_NAME, DEPT
FROM EMPLOYEE
WHERE TRUNC(TIME_CREATED) = TO_DATE('26/JAN/2011','dd/mon/yyyy')

更新:
正如Dave Costa在下面的注释中指出的那样，这将防止Oracle使用列TIME_CREATED的索引(如果存在).没有此问题的另一种方法是:

UPDATE:
As Dave Costa points out in the comment below, this will prevent Oracle from using the index of the column TIME_CREATED if it exists. An alternative approach without this problem is this:

SELECT EMP_NAME, DEPT
FROM EMPLOYEE
WHERE TIME_CREATED >= TO_DATE('26/JAN/2011','dd/mon/yyyy') 
      AND TIME_CREATED < TO_DATE('26/JAN/2011','dd/mon/yyyy') + 1

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