Question

I wrote this sql statement:

SELECT 
  e.id AS event_id, e.title, e.date, e.category, e.place, e.minAge, e.maxAge,
  p.id, p.name, p.coor, p.nz,
  a.user, a.event, COUNT(a.user) AS attending,
  i.user_id, i.event_id
FROM events AS e
LEFT JOIN attendance a ON a.event = e.id
LEFT JOIN places p ON p.id = e.place
LEFT JOIN invited_friends i ON ( i.event_id = e.id ) AND ( i.user_id = 0 )
GROUP BY e.id
ORDER BY attending DESC

This statement selects events from table events and join some tables. everything is good so far.
I have another table called: invited_friends.

event_id    bigint(20)    
user_id     int(11)   
owner       tinyint(1)

This table stores the user ids that invited to event.

The problem is that not every event is a private event, not every event got invited friends… the way I can tell if event is private or not is the column: category in event table, if it = 4 then it is a private event.

My inner join works, but it ignores all the public events because they have no invited friends.

How can I fix that?

Thanks in advance.

Answer 1

...
FROM events AS e
LEFT JOIN attendance a ON a.event = e.id
LEFT JOIN places p ON p.id = e.place
LEFT JOIN invited_friends i ON ( i.event_id = e.id ) AND ( i.user_id = 0 )

WHERE category != 4  or i.event_id is not null

...