postgres=# select * from test_var where(c1,c2) not in (select * from test_tmp);
2021-12-21 15:02:21.648 CST [8344] ERROR:  could not determine interpretation of row comparison operator = at character 37
2021-12-21 15:02:21.648 CST [8344] HINT:  Row comparison operators must be associated with btree operator families.
2021-12-21 15:02:21.648 CST [8344] STATEMENT:  select * from test_var where(c1,c2) not in (select * from test_tmp);
ERROR:  could not determine interpretation of row comparison operator =
LINE 1: select * from test_var where(c1,c2) not in (select * from te...
                                            ^
HINT:  Row comparison operators must be associated with btree operator families.

postgres=# select * from test_var where(c1,c2) not in (select * from test_tmp);
 c1 |  c2   
----+-------
 2  | test2
(1 row)

set search_path to oracle,pg_catalog;
create table test_var(c1 varchar2,c2 varchar2);
insert into test_var values('1','test1'),('1','test1'),('2','test1'),('2','test2');
create table test_tmp(c1 varchar2,c2 varchar2);
insert into test_tmp values('1','test1'),('2','test1');
select * from test_var where(c1,c2) not in (select * from test_tmp);