Table 「test.test」

testdb=# \d test
                        Table "test.test"
   Column   |       Type        | Collation | Nullable | Default 
------------+-------------------+-----------+----------+---------
 student_id | character(8)      |           |          | 
 subj       | character varying |           |          | 
 score      | integer           |           |          | 

testdb=# SELECT * FROM test;
 student_id | subj | score 
------------+------+-------
 S1000312   | 数学 |     0
 S2000637   | 国語 |    45
 S2000630   | 生物 |    82
(3 rows)

testdb=# SELECT * FROM test;
 student_id | subj | score 
------------+------+-------
 S1000312   | 数学 |     0
 S2000637   | 国語 |    45
 S2000630   | 生物 |    82
 S3000227   | 化学 |   100
 S2000314   | 地理 |    52
(5 rows)

testdb=# SELECT * FROM test;
 student_id | subj | score 
------------+------+-------
 S1000312   | 数学 |     0
 S2000630   | 生物 |    82
 S3000227   | 化学 |   100
 S2000314   | 地理 |    52
 S2000637   | 国語 |      
(5 rows)

testdb=# SELECT * FROM test;
 student_id | subj | score 
------------+------+-------
 S1000312   | 数学 |     0
 S3000227   | 化学 |   100
 S2000637   | 国語 |      
(3 rows)

testdb=# SELECT count(*) FROM test;
 count 
-------
     3
(1 row)