Laravel whereHas 多对多关系
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Laravel whereHas on Many-to-Many relationships
提问by Estern
I have two main tables with relationships many to many and a pivot table.
我有两个具有多对多关系的主表和一个数据透视表。
Model 'Type'
模型“类型”
public function attributes()
{
return $this->belongsToMany('App\Attribute', 'attribute_type');
}
Model 'Attribute'
模型“属性”
public function types()
{
return $this->belongsToMany('App\Type', 'attribute_type');
}
Pivot table 'attribute_type'
数据透视表“attribute_type”
Schema::create('attribute_type', function (Blueprint $table) {
$table->increments('id');
$table->integer('type_id')->unsigned();
$table->foreign('type_id')->references('id')->on('types');
$table->integer('attribute_id')->unsigned();
$table->foreign('attribute_id')->references('id')->on('attributes');
});
I want to show 5 attributes in random order which belong to the types of id < 10.
我想以随机顺序显示 5 个属于 id < 10 类型的属性。
$attributes = Attribute::whereHas('types', function ($query) {
$query->where('id', '<', '10');
})->orderByRaw("RAND()")->limit(5);
and for example
例如
$attribute->id
gives me "Undefined property: Illuminate\Database\Eloquent\Builder::$id"
给我“未定义的属性：Illuminate\Database\Eloquent\Builder::$id”
回答by Filip Koblański
All you have to do is execute query and get the collection with get()method like this:
您所要做的就是执行查询并使用如下get()方法获取集合：
$attributes = Attribute::whereHas('types', function ($query) {
$query->where('id', '<', '10');
})->orderByRaw("RAND()")->limit(5)
->get();
Now you are trying to iterate over the query builder which is giving you another query builder as a result of $attribute
现在您正在尝试迭代查询构建器，它为您提供另一个查询构建器作为结果 $attribute
