问题
So, I'm receiving the following error from Laravel framework; but I couldn't find why this framework is producing this error:
SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'participants' (SQL: select `participants`.*, `participants`.`message_id` as `pivot_message_id`, `participants`.`user_id` as `pivot_user_id`, `participants`.`created_at` as `pivot_created_at`, `participants`.`updated_at` as `pivot_updated_at` from `participants` inner join `participants` on `participants`.`id` = `participants`.`user_id` where `participants`.`deleted_at` is null and `participants`.`message_id` in (2))
My message/participants relationship looks like this:
public function participants()
{
return $this->belongsToMany('Namespace\Modules\Email\Models\Participant', 'participants', 'message_id', 'user_id')->withTimestamps();
}
and I'm trying to call it like this:
public function getAllMessages()
{
return Message::with('user')->with('participants')->get();
}
Why am I getting this error? What's going on?
Edit: Included full models
Message
class Message extends Eloquent
{
use PublishedTrait;
use SoftDeletingTrait;
/**
* The database table used by the model.
*
* @var string
*/
protected $table = 'messages';
/**
* The attributes that can be set with Mass Assignment.
*
* @var array
*/
protected $fillable = ['subject', 'user_id', 'body', 'status'];
/**
* The attributes that should be mutated to dates.
*
* @var array
*/
protected $dates = ['created_at', 'updated_at', 'deleted_at'];
/**
* Validation rules.
*
* @var array
*/
protected $rules = [
'subject' => 'required|max:255',
'body' => 'required',
];
/**
* User relationship
*
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function user()
{
return $this->belongsTo(Config::get('email.user_model'));
}
public function assets()
{
return $this->belongsToMany('Namespace\Modules\Assets\Models\Asset', 'message_assets');
}
/**
* Participants relationship
*
* @return \Illuminate\Database\Eloquent\Relations\HasMany
*/
public function participants()
{
return $this->belongsToMany('Namespace\Modules\Email\Models\Participant', 'participants', 'message_id', 'user_id')->withTimestamps();
}
/**
* Recipients of this message
*
* @return \Illuminate\Database\Eloquent\Relations\HasMany
*/
public function recipients()
{
return $this->participants()->where('user_id', '!=', $this->user_id);
}
/**
* Returns the latest message from a thread
*
* @return Namespace\Modules\Email\Models\Message
*/
public function getLatestMessageAttribute()
{
return $this->messages()->latest()->first();
}
/**
* Returns threads that the user is associated with
* @param $query
* @param $userId
* @return mixed
*/
public function scopeForUser($query, $userId)
{
return $query->join('participants', 'messages.id', '=', 'participants.message_id')
->where('participants.user_id', $userId)
->where('participants.deleted_at', null)
->select('messages.*');
}
/**
* Returns threads that the user is associated with
* @param $query
* @param $userId
* @return mixed
*/
public function scopeForUserWithDeleted($query, $userId)
{
return $query->join('participants', 'messages.id', '=', 'participants.message_id')
->where('participants.user_id', $userId)
->select('messages.*');
}
/**
* Returns messages that the user has sent
* @param $query
* @param $userId
* @return mixed
*/
public function scopeByUser($query, $userId)
{
return $query->where('user_id', $userId);
}
/**
* Returns threads with new messages that the user is associated with
* @param $query
* @param $userId
* @return mixed
*/
public function scopeForUserWithNewMessages($query, $userId)
{
return $query->join('participants', 'messages.id', '=', 'participants.message_id')
->where('participants.user_id', $userId)
->whereNull('participants.deleted_at')
->where(function ($query) {
$query->where('messages.updated_at', '>', $this->getConnection()->raw($this->getConnection()->getTablePrefix() . 'participants.last_read'))
->orWhereNull('participants.last_read');
})
->select('messages.*');
}
}
Participant
class Participant extends Eloquent
{
use SoftDeletingTrait;
/**
* The database table used by the model.
*
* @var string
*/
protected $table = 'participants';
/**
* The attributes that can be set with Mass Assignment.
*
* @var array
*/
protected $fillable = ['message_id', 'user_id', 'last_read'];
/**
* The attributes that should be mutated to dates.
*
* @var array
*/
protected $dates = ['created_at', 'updated_at', 'deleted_at', 'last_read'];
/**
* Thread relationship
*
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function message()
{
return $this->hasMany('Namespace\Modules\Email\Models\Message');
}
/**
* User relationship
*
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function user()
{
return $this->belongsTo(Config::get('email.user_model'));
}
}
回答1:
Answered via the Larachat official Slack:
The relationship is missing a pivot table for this to work. The second argument in the participants method is the pivot table to use:
public function participants()
{
return $this->belongsToMany('Namespace\Modules\Email\Models\Participant', 'PIVOT', 'message_id', 'user_id')->withTimestamps();
}
Therefore, you can't use participants as the pivot because it is one of the tables in the relationship, you need a message_participant pivot table.
回答2:
Your error is
...from `participants` inner join `participants` ...
You need to provide aliases for each reference, as in
...from `participants` p1 inner join `participants` p2 ...
and then use p1 and p2 in the correct places, for example
...on p1.`id` = p2.`user_id` ...
(I'm guessing on which is p1 and which is p2; you have to make that determination)
回答3:
Just make sure that same join applied for more than one time in a single query.
来源：https://stackoverflow.com/questions/31059595/sqlstate42000-syntax-error-or-access-violation-1066-not-unique-table-alias-o