Laravel Eloquent Accessor Strange Issue - laravel

Question

Laravel Version: 5.6.39
PHP Version: 7.1.19
Database Driver & Version: mysql 5.6.43
Description:
When I chain where and orWhere in a model accessor to count related model , I get wrong result and here is my query. the count is returned strange result without filtering by the calling event id,
class Event extends Model
{
protected $table = 'events';
public function registrations()
{
return $this->hasMany('App\Components\Event\Models\Registration','event_id','id');
}
public function getSeatsBookedAttribute()
{
return $this->registrations()
->where('reg_status','=','Confirmed')
->orWhere('reg_status','=','Reserved')
->count();
}
}
Steps To Reproduce:
the following queries return me the expected results, however In my knowledge the first query should return the same result if i am not wrong, so i think this is a potential bug.
class Event extends Model
{
public function getSeatsBookedAttribute()
{
return $this->registrations()
->whereIn('reg_status', ['Confirmed', 'Reserved'])
->count();
}
}
class Event extends Model
{
public function getSeatsBookedAttribute()
{
return $this->registrations()
->where(function($query){
$query->where('reg_status','Confirmed')
->orWhere('reg_status','Reserved');
})
->count();
}
}
and here is the query dump,
here is the query when I donot explicit group it.
"select count(*) as aggregate from events_registration where (events_registration.event_id = ? and events_registration.event_id is not null and reg_status = ? or reg_status = ?) and events_registration.deleted_at is null "
and here is the query when i group it explicitly,
select count(*) as aggregate from events_registration where events_registration.event_id = ? and events_registration.event_id is not null and (reg_status = ? or reg_status = ?) and events_registration.deleted_at is null

Answer 1

The reason this happens is because you're chaining where() and orWhere(). What you don't see behind the scenes is a where event_id = :event_id applying to your query. You end up with a query that looks something like this:
select * from registrations where event_id = :event_id and reg_status = 'Confirmed' or reg_status = 'Reserved'
In normal SQL you'd want to put the last 2 conditions in parentheses. For Eloquent, you'd need to do something like this:
return $this->registrations()->where(function ($query) {
$query->where('reg_status', 'Confirmed')
->orWhere('reg_status', 'Reserved');
});
You can chain the toSql() method on these chains to see the difference. Note, that in this case, I believe whereIn() is the semantically correct thing to do.
Eloquent can handle this for you, though; scroll down to "Counting Related Models" in the Querying Relations part of the Eloquent Relationships docs:
$posts = App\Event::withCount([
'registrations as seats_booked_count' => function ($query) {
$query->where('reg_status','Confirmed')
->orWhere('reg_status','Reserved');
}
])->get();