PostgreSQL compare a timestamp with timezone with a timestamp
create table test (ts1 timestamp without time zone, ts2 timestamp with time zone)



✓






insert into test (ts1, ts2) 
VALUES ('2019-01-07 21:43:00', '2019-01-07 20:43:37+01'), 
       ('2019-01-07 21:43:00', '2019-01-07 20:43:37-01')



2 rows affected






select *, 
       to_char(ts1, 'YYYYMMDDHH24MI') str_ts1, 
       to_char(ts2, 'YYYYMMDDHH24MI') str_ts2, 
       to_char(ts1, 'YYYYMMDDHH24MI') = to_char(ts2, 'YYYYMMDDHH24MI') compare 
from test



ts1                 | ts2                    | str_ts1      | str_ts2      | compare
:------------------ | :--------------------- | :----------- | :----------- | :------
2019-01-07 21:43:00 | 2019-01-07 19:43:37+00 | 201901072143 | 201901071943 | f      
2019-01-07 21:43:00 | 2019-01-07 21:43:37+00 | 201901072143 | 201901072143 | t      



db&lt;>fiddle here