关联模型之关联数量计数
https://learnku.com/docs/laravel/6.x/eloquent-relationships/5177#cc241a
关联模型中 关联计数
withCount() 这个方法
当使用withCount方法后，获取到的参数都是 *_count
比如：withCount('user') 则 获取到的是 user_count
例如：
$posts = App\Post::withCount('comments')->get();
foreach ($posts as $post) {
echo $post->comments_count;
}use Illuminate\Database\Eloquent\Builder;
$posts = App\Post::withCount(['votes', 'comments' => function (Builder $query) {
$query->where('content', 'like', 'foo%');
}])->get();
echo $posts[0]->votes_count;
echo $posts[0]->comments_count;还可以使用 as 方法 起一个别名
use Illuminate\Database\Eloquent\Builder;
$posts = App\Post::withCount([
'comments',
'comments as pending_comments_count' => function (Builder $query) {
$query->where('approved', false);
},
])->get();
echo $posts[0]->comments_count;
echo $posts[0]->pending_comments_count;