Oracle 21c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TABLE table1 (user_id, end_date) AS
  SELECT 1, DATE '1970-01-01' FROM DUAL;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
1970-01-01 00:00:00


UPDATE table1
SET   END_DATE = LAST_DAY(SYSDATE)
WHERE user_id = 1;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
2024-02-29 11:16:10


ROLLBACK;
UPDATE table1
SET   END_DATE = LAST_DAY(TRUNC(SYSDATE))
WHERE user_id = 1;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
2024-02-29 00:00:00


ROLLBACK;
UPDATE table1
SET   END_DATE = ADD_MONTHS(TRUNC(SYSDATE, 'MM'), 1) - INTERVAL '1' SECOND
WHERE user_id = 1;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
2024-02-29 23:59:59


ROLLBACK;
UPDATE table1
SET END_DATE = TRUNC(SYSDATE, 'MM') + INTERVAL '1' MONTH - INTERVAL '1' SECOND
WHERE user_id = 1;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
2024-02-29 23:59:59


ROLLBACK;
UPDATE table1
SET   END_DATE = LAST_DAY(TRUNC(SYSDATE)) + INTERVAL '23:59:59' HOUR TO SECOND
WHERE user_id = 1;
1 rows affected

SELECT * FROM table1;


USER_ID
END_DATE


1
2024-02-29 23:59:59