Oracle DateTime in Where Clause?

sql oracle time date-arithmetic
sanjeev40084 picture sanjeev40084 · Jul 19, 2011 · Viewed 454k times · Source

I have sql something like this:

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

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

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')

-> Took the greater than out

Any reason why?

Answer

Daniel Hilgarth picture Daniel Hilgarth · Jul 19, 2011

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')

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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