Oracle 18c

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CREATE TABLE your_table AS
SELECT 0 itemid, 0 checkin FROM dual UNION ALL
SELECT 1 itemid, 0 checkin FROM dual UNION ALL
SELECT 2 itemid, 1 checkin FROM dual UNION ALL
SELECT 3 itemid, 1 checkin FROM dual UNION ALL
SELECT 4 itemid, 1 checkin FROM dual;
5 rows affected

select * from your_table;


ITEMID
CHECKIN


0
0

1
0

2
1

3
1

4
1


MERGE INTO your_table tgt
  USING (SELECT itemid,
                checkin,
                overall_checkin
         FROM   (SELECT itemid,
                        checkin,
                        MAX(CASE WHEN checkin = 0 THEN 0 ELSE 1 END) OVER () overall_checkin
                 FROM   your_table
                 WHERE  itemid IN (1, 2, 3))
         WHERE  overall_checkin = 0) src
   ON (tgt.itemid = src.itemid) -- assuming that itemid is a primary/unique column
WHEN MATCHED THEN
  UPDATE SET tgt.checkin = 1;
select * from your_table;


ITEMID
CHECKIN


0
0

1
0

2
1

3
1

4
1


MERGE INTO your_table tgt
  USING (SELECT itemid,
                checkin,
                overall_checkin
         FROM   (SELECT itemid,
                        checkin,
                        MAX(CASE WHEN checkin = 0 THEN 0 ELSE 1 END) OVER () overall_checkin
                 FROM   your_table
                 WHERE  itemid IN (0, 1))
         WHERE  overall_checkin = 0) src
   ON (tgt.itemid = src.itemid) -- assuming that itemid is a primary/unique column
WHEN MATCHED THEN
  UPDATE SET tgt.checkin = 1;
2 rows affected

select * from your_table;


ITEMID
CHECKIN


0
1

1
1

2
1

3
1

4
1