Oracle 18c

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CREATE TABLE Historical (ID, LastReboot1, LastReboot2) AS
SELECT '4622', DATE '2022-09-11', DATE '2022-09-11' FROM DUAL UNION ALL
SELECT '0462', DATE '2021-09-21', DATE '2021-09-21' FROM DUAL UNION ALL
SELECT '0099', DATE '2021-10-19', DATE '2021-10-19' FROM DUAL;
3 rows affected

CREATE TABLE "CURRENT" (ID, LastReboot1, LastReboot2) AS
SELECT '4622', DATE '2022-09-18', DATE '2022-09-18' FROM DUAL UNION ALL
SELECT '0462', DATE '2022-09-20', DATE '2022-09-20' FROM DUAL;
2 rows affected

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
SELECT *
FROM   "CURRENT"
UNION ALL
SELECT *
FROM   historical h
WHERE  NOT EXISTS (SELECT 1 FROM "CURRENT" c WHERE h.id = c.id)


ID
LASTREBOOT1
LASTREBOOT2


4622
2022-09-18 00:00:00
2022-09-18 00:00:00

0462
2022-09-20 00:00:00
2022-09-20 00:00:00

0099
2021-10-19 00:00:00
2021-10-19 00:00:00

ID	LASTREBOOT1	LASTREBOOT2
4622	2022-09-18 00:00:00	2022-09-18 00:00:00
0462	2022-09-20 00:00:00	2022-09-20 00:00:00
0099	2021-10-19 00:00:00	2021-10-19 00:00:00