我觉得应该是:

$insert_query = "INSERT INTO student (NAME, ID, ADDRESS, SUBJECT, REMARKS)
VALUES ('AJAY', 11, 'SILK BOARD', 'IRO', 'AVERAGE'),
('RITESH', 12, 'KARTHIK NAGAR', 'IRO', 'GOOD'), 
('SUNNY', 13, 'HEBBAL', 'HR MODULE', 'GOOD'), 
('HEMAVATHI', 14, 'HEBBAL', 'TME', 'GOOD'),
('GURU', 15, 'HEBBAL', 'IRO', 'GOOD'), 
('SARITHA', 16, 'HEBBAL', 'IRO', 'GOOD'),
('NIHAAR', 17, 'MULTIPLEX', 'COMPUTERS', 'AVERAGE')";