examdb=# \d sample1 Table "test.sample1"

examdb=# \d sample1
                      Table "test.sample1"
 Column |         Type          | Collation | Nullable | Default 
--------+-----------------------+-----------+----------+---------
 id     | integer               |           |          | 
 name   | character varying     |           |          | 
 tel    | character varying(11) |           |          | 

examdb=# SELECT * FROM sample1;
 no | name |     tel     
----+------+-------------
  1 | 佐藤 | 08012345678
  2 | 田中 | 08022345678
  3 | 山田 | 08032345678
  4 | 佐藤 | 08042345678
(4 rows)

examdb=# SELECT id FROM (SELECT id FROM sample1) s1;
 id 
----
  1
  2
  3
  4
(4 rows)

examdb=# SELECT * FROM sample1 WHERE id =ANY (SELECT id FROM sample1 WHERE name = '佐藤');
 id | name |     tel     
----+------+-------------
  1 | 佐藤 | 08012345678
  4 | 佐藤 | 08042345678
(2 rows)

examdb=# SELECT * FROM sample1 WHERE id = (SELECT id FROM sample1 WHERE name = '田中');
 id | name |     tel     
----+------+-------------
  2 | 田中 | 08022345678
(1 row)

examdb=# SELECT (SELECT id FROM sample1 WHERE name = '田中');
 id 
----
  2
(1 row)