create table t (
a int,
b int without system versioning
) with system versioning;
insert into t values(1, 2);
insert into t values(3, 4);
select * from t;
a	b
1	2
3	4
select a from t for system_time as of timestamp now(6);
a
1
3
select a, b, b+0 from t for system_time as of timestamp now(6);
a	b	b+0
1	2	2
3	4	4
select * from t for system_time as of timestamp now(6);
a	b
1	2
3	4
select count(*) from t for system_time as of timestamp now(6) group by b;
count(*)
1
1
select * from t for system_time as of timestamp now(6) order by b asc;
a	b
1	2
3	4
select * from t for system_time as of timestamp now(6) order by b desc;
a	b
3	4
1	2
select * from t for system_time as of timestamp now(6) group by a having a=2;
a	b
select * from t for system_time as of timestamp now(6) group by b having b=2;
a	b
1	2
select a from t for system_time as of timestamp now(6) where b=2;
a
1
select a from t for system_time as of timestamp now(6) where b=NULL;
a
select a from t for system_time as of timestamp now(6) where b is NULL;
a
select count(*), b from t for system_time as of timestamp now(6) group by b having b=NULL;
count(*)	b
select a, b from t;
a	b
1	2
3	4
create or replace table t (
a int,
b int not null without system versioning
) with system versioning;
insert into t values (1, 2), (3, 4);
select * from t for system_time as of timestamp now(6);
a	b
1	2
3	4
select * from t for system_time as of timestamp now(6) where b is NULL;
a	b
drop table t;