filter timestamp column in SQL Oracle - sql

Question

I have a table with a Timestamp column which I need to filter after '2020-08-26', but every solution won't work
RUN_TIME
2020-07-22 04:22:07
2020-07-22 04:34:07
2020-07-22 04:45:07
2020-07-22 04:50:07
2020-07-22 04:55:08
I tried the below queries:
WHERE CAST (RUN_DATE AS DATE) >= TO_DATE('2020-08-26', 'yyyy-mm-dd')
WHERE to_date(RUN_DATE, 'YYYY-MM-DD hh24:mi:ss') >= to_date('26-08-2020 23:59:59', 'YYYY-MM-DD hh24:mi:ss')
WHERE RUN_DATE >= TO_TIMESTAMP('26-08-2020 23:59:59')

Answer 1

Use a TIMESTAMP literal:
SELECT *
FROM table_name
WHERE run_time >= TIMESTAMP '2020-08-27 00:00:00';
or, use a DATE literal:
SELECT *
FROM table_name
WHERE run_time >= DATE '2020-08-27';
or, use TO_TIMESTAMP with a format model:
SELECT *
FROM table_name
WHERE run_time >= TO_TIMESTAMP( '2020-08-27', 'YYYY-MM-DD' );
or, use TO_DATE with a format model:
SELECT *
FROM table_name
WHERE run_time >= TO_DATE( '2020-08-27', 'YYYY-MM-DD' );
Which for the sample data:
CREATE TABLE TABLE_NAME ( run_time TIMESTAMP(6) );
INSERT INTO table_name ( run_time )
SELECT TIMESTAMP '2020-07-22 04:22:07' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-07-22 04:34:07' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-07-22 04:45:07' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-07-22 04:50:07' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-07-22 04:55:08' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-08-26 23:59:59.999999' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-08-27 00:00:00' FROM DUAL;
All output:
| RUN_TIME |
| :------------------------ |
| 27-AUG-20 00.00.00.000000 |
db<>fiddle here

Answer 2

Just:
where run_date >= date '2020-08-26'
That's direct filtering against a date literal.
run_date is a timestamp already, so you should not attempt to convert it. Also, to_timestamp() takes a second argument, which specifies the format of the string; without it, it defaults to the nls_timestamp_format of your session (or database), which may not be what you expect