mysql - 如何限制 Laravel 中特定外键值的行数

Question

我们有一个 posts 表，user_id 是外键例如，我想为这些用户选择帖子

$users=[1,2,13,16,17,19];
$posts = Post::whereIn('user_id', $users)->paginate(10);

但我希望用户 1 和 2 在输出中只有两个帖子，对于其余用户，帖子数量没有限制。

Note: User 1 and 2 are not always within the $users array, and due to the condition, one or both of them may not be in the array.

你有解决办法吗？

Answer 1

您无法在单个查询中实现此目的，我们需要像这样单独进行处理

$users=[1,2,13,16,17,19];
// first take all the post except the two
$posts = Post::whereIn('user_id', $users)->whereNotIn('user_id', [1,2])->get()->toArray();
// then take one user 1 post in desc and limit it by 2
$userOnePost = Post::whereIn('user_id', $users)->where('user_id', 1)->limit(2)->orderBy('post.id', 'desc')->get()->toArray();
// then take one user 2 post in desc and limit it by 2
$userTwoPost = Post::whereIn('user_id', $users)->where('user_id', 2)->limit(2)->orderBy('post.id', 'desc')->get()->toArray();

// merge all the array
$allPost = array_merge(posts,$userOnePost,userTwoPost);