create table t (
id int primary key,
x int,
row_start SYS_DATATYPE as row start invisible,
row_end SYS_DATATYPE as row end invisible,
period for system_time (row_start, row_end)
) with system versioning;
insert t values (1, 2);
replace t values (1, 3);
select *, current_row(row_end) as current from t for system_time all order by x;
id	x	current
1	2	0
1	3	1
drop table t;
create table t (
id int unique,
x int,
row_start SYS_DATATYPE as row start invisible,
row_end SYS_DATATYPE as row end invisible,
period for system_time (row_start, row_end)
) with system versioning;
insert t values (1, 2);
replace t values (1, 3);
select *, current_row(row_end) as current from t for system_time all order by x;
id	x	current
1	2	0
1	3	1
drop table t;