如何使用Eloquent在Laravel中编写以下SQL查询？

Question

I want to write a query in Laravel to retrive all the posts that a particular user has viewed. The user_id and the post_id is saved in the table named WatchHistory .

SELECT *
FROM Post
WHERE post_id = (
     SELECT post_id
     FROM WatchHistory
     WHERE user_id = $user_id
);

I tried the following :

$posts = Post::whereIn('post_id', function($query){
        $query->select('post_id')
            ->from(with(new WatchHistory)->getTable())
            ->where('user_id',$user_id);
        })->get();

But it gives me an error that the variable user_id is not defined.

Answer 1

You should try this :

POST::whereIn('post_id', function($query) use($user_id){
            $query->select('post_id')
                ->from(with(new WATHCHISTORY)->getTable())
                ->where('user_id',$user_id);
            })->get();

Hope this work for you !!!!

Answer 2

Try this one,

If your user's id is in variable $user_id , you can do it like,

DB::table('post')->whereIn('post_id',
    DB::table('watchhistory')->where('user_id',$user_id)->pluck('post_id')
)->get();