Oracle 23c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
ALTER SESSION SET NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF';
CREATE TABLE table_name (timestamp_column) AS
SELECT TIMESTAMP '2024-01-13 00:10:02.000000000' FROM DUAL UNION ALL
SELECT TIMESTAMP '2024-01-01 00:23:59.000000000' FROM DUAL UNION ALL
SELECT TIMESTAMP '2024-01-02 00:00:00.000000000' FROM DUAL;
3 rows affected

UPDATE table_name
SET timestamp_column = CAST(TRUNC(timestamp_column, 'DD') AS TIMESTAMP)
                     + EXTRACT(MINUTE FROM timestamp_column) * INTERVAL '1' HOUR
                     + EXTRACT(SECOND FROM timestamp_column) * INTERVAL '1' MINUTE;
3 rows affected

SELECT *
FROM   table_name;


TIMESTAMP_COLUMN


2024-01-13 10:02:00.000000000

2024-01-01 23:59:00.000000000

2024-01-02 00:00:00.000000000