Yet another query help request

Question

Imagine the following statement
INSERT table2
SELECT TO_CHAR(col1,'YYYY-WW'), col2, col3, AVG(col4) FROM table1
WHERE TO_CHAR(table1.col1,'YYYY-WW') != TO_CHAR(SYSDATE,'YYYY-WW')
AND (TO_CHAR(table1.col1,'YYYY-WW'), col2)
NOT IN (SELECT col1, col2 FROM table2)
GROUP BY TO_CHAR(col1,'YYYY-WW'), col2, col3;I want to group by calendarweek and calculate an average value. My problem is the corresponding "cleanup" script. I want to create a query which deletes these rows, which are older than ... three years. All I've got for that task is the VARCHAR2-field formatted like "2006-32".
If I want to run a direct comparison like
DELETE FROM table2 WHERE SYSDATE - to_date(col1,'YYYY-WW') > 1095; I get an ORA-01820 error. :-( I'm trying to get a grip on this problem for two days now! Can someone please help me. desparate

Answer 1

what i mean is:
if executed today:
2003-31 will be deleted as we can see it greater than 3 that is,3years
2003-32 wont be deleted as its less than or equal to 3 years old
SQL> select (TO_CHAR(SYSDATE,'YYYY')-(TO_CHAR('2003'))) + (to_char(sysdate,'ww')-(31))/12 from dual;
(TO_CHAR(SYSDATE,'YYYY')-(TO_CHAR('2003')))+(TO_CHAR(SYSDATE,'WW')-(31))/12
3.08333333
SQL> select (TO_CHAR(SYSDATE,'YYYY')-(TO_CHAR('2003'))) + (to_char(sysdate,'ww')-(32))/12 from dual;
(TO_CHAR(SYSDATE,'YYYY')-(TO_CHAR('2003')))+(TO_CHAR(SYSDATE,'WW')-(32))/12
3
SQL> select to_char(sysdate,'ww') from dual;
TO
32