Laravel在whereIn子句中的限制

Question

I'm using laravel 5.7

I have query with whereIn clause

In my controller I have query like this:

$post = Post::whereIn('reply_from_id', [1,2])
            ->orderBy('created_at', 'desc')->get();

I get output like this:

[
    {
        "id": 3,
        "title": "test reply id 2",
        "reply_from_id": 2
    },
    {
        "id": 4,
        "title": "test reply id 1",
        "reply_from_id": 1
    },
    {
        "id": 5,
        "title": "test reply id 1 again",
        "reply_from_id": 1
    },
    {
        "id": 6,
        "title": "test reply id 1 again and again",
        "reply_from_id": 1
    },
    {
        "id": 7,
        "title": "test reply id 2 again",
        "reply_from_id": 2
    }
]

I want to limit output only show 2 data every ID

for example:

[
    {
        "id": 3,
        "title": "test reply id 2",
        "reply_from_id": 2
    },
    {
        "id": 4,
        "title": "test reply id 1",
        "reply_from_id": 1
    },
    {
        "id": 5,
        "title": "test reply id 1 again",
        "reply_from_id": 1
    },
    {
        "id": 7,
        "title": "test reply id 2 again",
        "reply_from_id": 2
    },

]

I try using take() like this:

$post = Post::whereIn('reply_from_id', [1,2])
            ->take(2)
            ->orderBy('created_at', 'desc')->get();

But this is only show data like this

[
    {
        "id": 3,
        "title": "test reply id 2",
        "reply_from_id": 2
    },
    {
        "id": 4,
        "title": "test reply id 1",
        "reply_from_id": 1
    }
]

How to limit data in whereIn clause ?

Answer 1

You can group by reply_from_id to get 1 record for every id

Use the use keyword to bind variables into the function's scope.

Closures may inherit variables from the parent scope. Any such variables must be declared in the function header [using use].

$everyHow = 3;
$ids      = [1,2];
$post     = Post::whereIn("posts.id", function ($query) use ($everyHow, $ids) {
    $query->select("p.id")->from('posts p')
    ->whereRaw('p.id = posts.id')
    ->whereIn("p.reply_from_id", $ids)
    ->orderBy("p.id", "desc")->limit($everyHow);
})->get();

EDIT

Explanation: Fetching properly data under the consideration of id which is a primary key and 3 records every reply_from_id must have a unique id to identify and fetch in query hence, I took wherein id , is that clear?

Answer 2

$post = Post::whereIn('reply_from_id', [1,2])
            ->limit(1)
            ->orderBy('created_at', 'desc')->get();

$post = Post::whereIn('reply_from_id', [1,2])
            ->limit(1)
            ->orderBy('created_at', 'desc')->first();