c# - MySql 内连接，如果值等于 0，则为 "OR"

Question

所以我有这个内部连接

SELECT IDEvent,events.IDSubject,events.month,events.year
FROM events
    INNER JOIN subjects ON events.IDSubject = subjects.IDSubject
    INNER JOIN classes ON subjects.IDClass = classes.IDClass
    INNER JOIN students ON classes.IDClass = students.IDClass
WHERE events.month=10
    AND events.year=2015
    AND (students.DNI=DNI OR events.IDSubject='0')`

我想要做的是根据用户 IDSubject 选择所有事件，并且如果还有一些 IDSubject=0 的事件，我可以获取依赖于用户的事件，但无法获取IDSubject=0 的，有人知道如何正确执行此操作吗？

我的数据库模型(如果有人需要的话)

Answer 1

SELECT IDEvent,events.IDSubject,events.month,events.year
FROM events
      INNER JOIN subjects ON events.IDSubject = subjects.IDSubject
      INNER JOIN classes ON subjects.IDClass = classes.IDClass
      INNER JOIN students ON classes.IDClass = students.IDClass
WHERE events.month=10
      AND events.year=2015
      AND students.DNI=DNI
UNION SELECT IDEvent, events.IDSubject ,events.month ,events.year
      FROM events WHERE IDSubject='0'