Postgres 14

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select version();

version

PostgreSQL 14.10 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-20), 64-bit

SELECT 1

create table your_table (
  t_stamp timestamptz,
  status_val int
);

insert into your_table (t_stamp, status_val) values
('2022-04-21 08:00', '0'),
('2022-04-21 08:01', '0'),
('2022-04-21 08:02', '3'),
('2022-04-21 08:03', '1'),
('2022-04-21 08:04', '1'),
('2022-04-21 08:05', '0');
  
select * from your_table;

CREATE TABLE

INSERT 0 6

t_stamp
status_val

2022-04-21 08:00:00+01
0

2022-04-21 08:01:00+01
0

2022-04-21 08:02:00+01
3

2022-04-21 08:03:00+01
1

2022-04-21 08:04:00+01
1

2022-04-21 08:05:00+01
0

SELECT 6

with mark_repeats as (
  select t_stamp, status_val,
         coalesce(
           status_val = lag(status_val) over (order by t_stamp),
           false
         ) as is_repeat
    from your_table
)
select t_stamp, status_val
  from mark_repeats
 where not is_repeat;

t_stamp
status_val

2022-04-21 08:00:00+01
0

2022-04-21 08:02:00+01
3

2022-04-21 08:03:00+01
1

2022-04-21 08:05:00+01
0

SELECT 4

t_stamp	status_val
2022-04-21 08:00:00+01	0
2022-04-21 08:01:00+01	0
2022-04-21 08:02:00+01	3
2022-04-21 08:03:00+01	1
2022-04-21 08:04:00+01	1
2022-04-21 08:05:00+01	0