左连接查询错误

Question

我有两个表事件和enrolledevents当一个学生注册一个事件的studentId和eventId存储在enrolledevents表 现在我想获得所有未注册的事件的学生。

我的表： 事件表

EnrolledEvents

任何一个可以给我我试过很多查询的查询，但我没有得到的结果

SELECT 
    * 
FROM 
    events 
     LEFT JOIN 
    enrolledevents ON events.event_id = enrolledevents.eevent_id 
WHERE 
    event_occurance = 'daily' 
     AND status = '1' 
     AND (enrolledevents.estudent_id NOT IN ('1') 
     AND enrolledevents.eevent_id NOT IN ('3')) 

Answer 1

移动下面WHERE条件到JOIN ON子句

AND (enrolledevents.estudent_id NOT IN ('1') 
    AND enrolledevents.eevent_id NOT IN ('3')) 

像

SELECT 
    * 
FROM 
    events 
     LEFT JOIN 
    enrolledevents ON events.event_id = enrolledevents.eevent_id 
        AND enrolledevents.estudent_id <> '1' 
        AND enrolledevents.eevent_id <> '3' 
WHERE 
    events.event_occurance = 'daily' 
     AND events.status = '1';