LIKE Operator to ignore the time part of DATE type?

Question

Hi,
is it allowed to use the LIKE operator on DATE Type to ignore the time-part in the DATE?
Nothing found in the manual, but seems to me that it works.
1. SELECT * FROM test_date WHERE tst_date LIKE to_date('01.01.2003 13:33:33','DD.MM.YYYY HH24:MI:SS') ;
2. SELECT * FROM test_date WHERE tst_date LIKE to_date('01.01.2003','DD.MM.YYYY') ;
3. SELECT * FROM test_date WHERE tst_date LIKE trunc(to_date('01.01.2003 00:00:00','DD.MM.YYYY HH24:MI:SS'));
4. SELECT * FROM test_date WHERE to_date('01.01.2003 13:33:33','DD.MM.YYYY HH24:MI:SS') LIKE tst_date;
5. SELECT * FROM test_date WHERE tst_date BETWEEN to_date('01.01.2003 00:00:00','DD.MM.YYYY HH24:MI:SS') AND to_date('01.01.2003 23:23:59','DD.MM.YYYY HH24:MI:SS');
6. SELECT * FROM test_date WHERE tst_date >= TO_DATE('01.01.2003 00:00:00','DD.MM.YYYY HH24:MI:SS') AND tst_date < TO_DATE('01.01.2003')+1;
7. SELECT * FROM test_date WHERE TRUNC(tst_date) = TRUNC(TO_DATE('01.01.2003 00:00:00','DD.MM.YYYY HH24:MI:SS'));
Result for 1-7 is the same.
What is the preferred Solution?
Solution 5 is bad, because index on TST_DATE column could not be used.
Solution 1 - 3 is the same using the LIKE operator.
Any comments?
Thanks, Markus
GEMS IT

Answer 1

Oh, sorry, LIKE-Operator solutions do also not use an Index :-(. Only 5. and 6.
Sample-Script:
CREATE TABLE TEST_DATE
TST_DATE DATE
CREATE INDEX MEDVIEW.TEST_DATE_IDX
ON MEDVIEW.TEST_DATE(TST_DATE);
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/01/2003 12:00:00 AM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/01/2003 12:45:13 PM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/01/2003 08:11:55 AM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/01/2003 12:00:00 AM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/01/2003 09:33:16 AM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/02/2003 07:45:00 AM', 'MM/DD/YYYY HH:MI:SS AM'));
INSERT INTO TEST_DATE ( TST_DATE ) VALUES (
TO_Date( '01/02/2003 07:33:00 PM', 'MM/DD/YYYY HH:MI:SS AM'));
COMMIT;