Laravel Eloquent union models from relationsships - sql

Question

I have a user who can have meetings from different relationships.He can be directly assigned to a meeting with one too many relationships, he can have user groups with many too many relationships that can have meetings with many too many relationships, and he can be responsible for a meeting with a relationship of one to many.
I want to get all meetings for one user. I don't want to merge the collections because I want to be able to use features like where directly in the database. My attempt is to merge all meeting ids and then get the meetings via 'whereIn'.
$ids = $this->meetings()->select('meetings.id')
->union($this->meetingsFromGroups()->select('meetings.id'))
->union($this->responsibleMeetings()->select('meetings.id'));
return Meeting::whereIn('id', $ids)->get();
When I execute this, I get this error:
"SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'union (select `meetings`.`id` from `meetings` inner join `meeting_user_group` on' at line 1 (SQL:...)"
The SQL that is executed:
select *
from `meetings`
where `id` in (
(
select `meetings`.`id`
from `meetings`
inner join `meeting_user` on `meetings`.`id` = `meeting_user`.`meeting_id`
where `meeting_user`.`user_id` = 1
)
union
(
select `meetings`.`id`
from `meetings`
inner join `meeting_user_group` on `meeting_user_group`.`meeting_id` = `meetings`.`id`
inner join `user_groups` on `user_groups`.`id` = `meeting_user_group`.`user_group_id`
inner join `user_user_group` on `user_user_group`.`user_group_id` = `user_groups`.`id`
where `user_user_group`.`user_id` = 1
)
union
(
select `meetings`.`id`
from `meetings`
where `meetings`.`responsible_id` = 1
and `meetings`.`responsible_id` is not null
)
)
The relations:
public function responsibleMeetings(): HasMany {
return $this->hasMany(Meeting::class, 'responsible_id');
}
public function meetings(): BelongsToMany {
return $this->belongsToMany(Meeting::class)->withTimestamps();
}
public function meetingsFromGroups(): HasManyDeep {
return $this->hasManyDeepFromRelations($this->userGroups(), (new UserGroup())->meetings());
}
I'm using the package Staudenmeir\EloquentHasManyDeep for meetingsFromGroups.
I can't use union on the whole meeting, because then I would get
SQLSTATE[21000]: Cardinality violation: 1222 The used SELECT statements have a different number of columns
because of the pivot fields.
How would the SQL have to change for it to work, and how can I do that with Eloquent?

Answer 1

By default whereIn expects array to perform IN() clause on array items but in your case your are sending a union query which is why it is throwing error.
$ids = $this->meetings()->select('meetings.id')
->union($this->meetingsFromGroups()->select('meetings.id'))
->union($this->responsibleMeetings()->select('meetings.id'))
->pluck('id')->all();
return Meeting::whereIn('id', $ids)->get();
Additionally whereIn accepts a closure method also but not sure how would you call these relateables $this->meetings() ,$this->meetingsFromGroups() & $this->responsibleMeetings() inside closure
return Meeting::whereIn('id', function($query){
$query->select('...')
...;
})->get();