Invalid month-SQL - sql

Question

for rate in ( select tgt.carrier_code, tgt.tc_code, tgt.exp_date, (TO_date(src.eff_date,'DD/MM/RRRR HH24:MI:SS') - 1/(24*60*60)) eff_date from mira_rate
tgt, mira_rate_dummy src
where src.carrier_code=tgt.carrier_code and src.tc_code=tgt.tc_code)
loop
update mira_rate
set exp_date=to_date(rate.eff_date,'DD/MM/RRRR HH24:MI:SS')
end loop;
When i run this query I am getting Format error.
How to correct this? I treid giving diff to_date options it says some .
Pls suggest

Answer 1

Assuming the question title means you got ORA-01843: not a valid month, this is probably down to your unnecessary to_date() calls as a_horse_with_no_name suggested, but it depends on your NLS_DATE_FORMAT setting. It's easy enough to reproduce, but only by making an assumption about your environment:
alter session set nls_date_format = 'MM/DD/RRRR';
select to_date(eff_date, 'DD/MM/RRRR HH24:MI:SS') from (
select (to_date(sysdate, 'DD/MM/RRRR HH24:MI:SS') - 1/(24*60*60)) eff_date
from dual
);
which gives:
select (to_date(sysdate, 'DD/MM/RRRR HH24:MI:SS') - 1/(24*60*60)) eff_date
*
ERROR at line 2:
ORA-01843: not a valid month
or since the error's pointing to the inner select, just:
SQL> select to_date(sysdate, 'DD/MM/RRRR HH24:MI:SS') from dual;
select to_date(sysdate, 'DD/MM/RRRR HH24:MI:SS') from dual
*
ERROR at line 1:
ORA-01843: not a valid month
The issue is that you're doing an implicit conversion of your date; effectively:
select to_date(to_char(sysdate, 'MM/DD/RRRR'), 'DD/MM/RRRR HH24:MI:SS')
The implicit conversion renders that as 01/28/2013 (or with the time as well, if that's in your NLS date mask), and when you then try to convert that back to a date with mask DD/MM/RRRR ... it's trying to use '28' as the month, which is clearly invalid.
If your fields are already dates then your to_date() calls are pointless, confusing and in this case causing an error. You should be able to do:
for rate in (select tgt.carrier_code, tgt.tc_code, tgt.exp_date,
src.eff_date - interval '1' second as eff_date
from mira_rate tgt, mira_rate_dummy src
where src.carrier_code=tgt.carrier_code and src.tc_code=tgt.tc_code)
loop
update mira_rate
set exp_date = rate.eff_date;
end loop;
I changed your - 1/(24*60*60) to - interval '1' second because I find that clearer, but it has the same effect.
Your update doesn't have a where clause though, but since it was missing a ; that might have been lost in transcription.