TO_DAYS equivalant in Oracle

Question

I have a db table (calendar)
calendar_id NUMBER(15) NOT NULL,
event_name VARCHAR2(20) NOT NULL,
event_date DATE NOT NULL,
EVENT_DESCRIPTION VARCHAR2(4000) NOT NULL,
date_stamp     DATE NOT NULL,
admin_id     NUMBER(15) NOT NULL,
CONSTRAINT PK_CALENDAR PRIMARY KEY (calendar_id )
and have to replace the following sql from MySql to an oracle version.
SELECT CALENDAR_ID, EVENT_DATE, EVENT_DESCRIPTION, EVENT_NAME FROM calendar WHERE TO_DAYS(EVENT_DATE) >= TO_DAYS('09-28-03 ') ORDER BY EVENT_DATE
Could someone let me know how to do this in Oracle.
Thanks

Answer 1

TO_DATE on a date is a bug in your code. TO_DATE accepts character input, if you input a date, it will be implicitly converted to a character parameter, and then converted back to a date result.
When using implicit type conversion in this way, no format mask is specified. If you are lucky you may get the same date back, if you are not you won't.
SQL> create table t (d date);
Table created.
SQL> alter session set nls_date_format = 'MM/DD/RR';
Session altered.
SQL> insert into t values (date '1901-01-01');
1 row created.
SQL> insert into t select to_date(d) from t;
1 row created.
SQL> select * from t;
D
01/01/01
01/01/01
SQL> alter session set nls_date_format = 'MM/DD/YYYY';
Session altered.
SQL> select * from t;
D
01/01/1901
01/01/2001
SQL>Apologies in advance for any borked formatting courtesy of the Formatting of posts.