示例

drop table if exist test;
drop table if exist test_2025_01_01;

create table test(id serial primary key, info text);
create table test_2025_01_01() inherits (test);
insert into test(info) values('info1');
insert into test_2025_01_01(info) values('info2');

postgres=# begin;
BEGIN
postgres=# truncate test;
TRUNCATE TABLE
postgres=# select * from test;
 id | info
----+------
(0 rows)

postgres=# select * from test_2025_01_01;
 id | info
----+------
(0 rows)

postgres=# rollback;
ROLLBACK
postgres=# begin;
BEGIN
postgres=# truncate only test;
TRUNCATE TABLE
postgres=# select * from test_2025_01_01;
 id | info
----+-------
  2 | info2
(1 row)

postgres=# select * from test;
 id | info
----+-------
  2 | info2
(1 row)

postgres=#
postgres=# select * from only test;
 id | info
----+------
(0 rows)

postgres=# rollback;
ROLLBACK
postgres=#

only  是针对父表而言，如果是子表，是无所谓的关键字了，起不了什么作用。