Laravel：查找数据透视表记录是否存在

Question

I have two models which are joined by a pivot table, User and Task .

I have a user_id and a task_id .

What is the neatest way to check whether a record exists for this combination of user and task?

Answer 1

You have a couple options depending on your situation.

If you already have a User instance and you want to see if it has a task with a certain id, you can do:

$user = User::find(1);
$hasTask = $user->tasks()->where('id', $taskId)->exists();

You can reverse this if you have the Task instance and want to check for a user:

$task = Task::find(1);
$hasUser = $task->users()->where('id', $userId)->exists();

If you just have the ids, without an instance of each, you could do the following:

$hasPivot = User::where('id', $userId)->whereHas('tasks', function ($q) use ($taskId) {
        $q->where('id', $taskId);
    })
    ->exists();

Answer 2

你可能会搜索这个吗？

$users = User::has('task')->get();

Answer 3

You can also try this, this is working in Laravel 5.7

$user = User::find(1);
$hasTask = $user->tasks->contains($taskId);

But the better way will be

$hasTask = $user->tasks()->where('tasks.id', $taskId)->exists();

Answer 4

对我来说最容易阅读的是：

$user->tasks()->exists();

Answer 5

You can use the code below:

$user = User::find(1);

$hasTask = $user->tasks()->where('task_id', $taskId)->exists();