Oracle 18c

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create table t1 (id number primary key);
insert into t1 select level from dual connect by level <= 3;
3 rows affected

create table t2 (id number primary key);
insert into t1 select level + 10 from dual connect by level <= 3;
3 rows affected

select * from t1;

ID

1

2

3

11

12

13

rollback;
select * from t1;

ID

1

2

3