Conversion bug of to_date(x,yyyy/mm/dd)

Question

Dear Madam or Sir,
my name is Christian Butzke and I am working for Perpetuum Co. Ltd. in Japan.
I am using Oracle Database 9. I encountered maybe a bug of the to_date sql function.
I am not sure where to post bug reports. I search one hour on the Oracle homepage for an email address, but there was none, so I tried this forum. If this forum does not handle bugs, I am sorry.
The following script should show after each select command one row with 2005-01-01 00:00:00.0.
CREATE TABLE test ("df" DATE);
INSERT INTO test VALUES ('2005-01-01');
SELECT TO_DATE("df",'yyyy/mm/dd'), "df" FROM test;
SELECT * FROM test WHERE "df">='2005-01-01';
SELECT * FROM test WHERE TO_DATE("df",'yyyy/mm/dd')>='2005-01-01';
DROP TABLE test;
Instead the first select returns:
TO_DATE(DF,YYYY/MM/DD)     DF
0005-01-01 00:00:00.0     2005-01-01 00:00:00.0
The second select returns correctly the row
DF
2005-01-01 00:00:00.0
However, the last select returns nothing.
This should be a bug, shouldn't it be?
With regards,
Christian-Manuel Butzke
Perpetuum Co. Ltd.

Answer 1

I am using Oracle Database 9. I encountered maybe a
bug of the to_date sql function.the bug is in your code, not in oracle!
CREATE TABLE test ("df" DATE);
INSERT INTO test VALUES ('2005-01-01');this is poor coding, you should use
insert into test values (to_date('2005-01-01', 'YYYY-MM-DD'));
SELECT TO_DATE("df",'yyyy/mm/dd'), "df" FROM test;this is also buggy code, you should use
select "dt" from test
to_date(date) is a source of errors
SELECT * FROM test WHERE "df">='2005-01-01';again, this is poor coding, you compare string with date. Prefer where "df" >= to_date('2005-01-01', 'YYYY-MM-DD')
SELECT * FROM test WHERE
TO_DATE("df",'yyyy/mm/dd')>='2005-01-01';same as above