Sql code taking long time

Question

Hello Everyone,
In Oracle 10g,I have table emp_history and column name hired_date,which has the
values in the following format 7/8/2011 12:55:55 PM
('mm/dd/yyyy hh12:mi:ss AM') ana this table has more than 50 thousand records,
when I tried to get the employees whose hired_date between 01/04/2011 and 30/04/2011
its taking long time(16 to 19 minutes) just to fetch 845 records.
I tried the following codes,
select * from emp_history where to_char(hired_date,'mmddyyyy') between
04012011' and 04302011' and ...;and
  select * from emp_history where to_char(hired_date,'ddmmyyyy') between
'01042011' and 30042011' and ....It having some other where condition also but If I commented the above where condition alone its working fine,
If I include i taking long time.
Can anyone tell me how to modify the code.
Thank you.
Edited by: Gurujothi on Aug 3, 2012 4:21 AM

Answer 1

Do you have an index on HIRED_DATE column? If yes then your index will not be considered.
You need to write your query like this.
select *
  from emp_history
where hired_date between to_date('04012011', 'mmddyyyy') and (to_date('04302011', 'mmddyyyy') + 1) - interval '1' second
   and ...;Use of function on a column makes that column index unusable.
Further to assist you please read the following link and post the required details
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