mysql> select * from score limit 4 ; +------------+----------+-------+ | student_id | event_id | score | +------------+----------+-------+ | 1 | 1 | 20 | | 3 | 1 | 20 | | 4 | 1 | 18 | | 5 | 1 | 13 | +------------+----------+-------+ 4 rows in set (0.00 sec)
mysql> select * from event ; +------------+------+----------+ | date | type | event_id | +------------+------+----------+ | 2004-09-03 | Q | 1 | | 2004-09-06 | Q | 2 | | 2004-09-09 | T | 3 | | 2004-09-16 | Q | 4 | | 2004-09-23 | Q | 5 | | 2004-10-01 | T | 6 | +------------+------+----------+ 6 rows in set (0.00 sec)
mysql> select * from student limit 4 ; +--------+-----+------------+ | name | sex | student_id | +--------+-----+------------+ | Megan | F | 1 | | Joseph | M | 2 | | Kyle | M | 3 | | Katie | F | 4 | +--------+-----+------------+ 4 rows in set (0.00 sec)
select student.name, student.student_id, event.date, event.event_id, event.type from student, event left join score on student.student_id = score.student_id and event.event_id=score.event_id where score.score is null ;
ERROR 1054 (42S22): Unknown column 'student.student_id' in 'on clause' 왜 이런 애러가 나는지 모르겠네요