How to Retrieve Posts from Users You Follow in a Social Network using Laravel Join Operations?

Laravel Join with Three Tables for Social Network Functionality

In Laravel, when working with multiple tables, it's essential to understand how to perform join operations efficiently. In this scenario, we aim to retrieve posts from users that a specific user is following.

Database Tables

We have three tables involved:

• Users: id
• Followers: user_id, follower_id
• Shares: user_id

Query Using Database Queries

One option is to use Laravel's database query builder. Here's how you can construct the query:

<code class="php">$shares = DB::table('shares')
    ->leftjoin('followers', 'shares.user_id', '=', 'followers.follower_id')
    ->leftjoin('users', 'followers.user_id', '=', 'users.id')
    ->where('users.id', 3)
    ->where('shares.user_id', 'followers.follower_id')
    ->get();</code>

Model Approach

Alternatively, you can use Laravel's Eloquent ORM for a more structured and type-safe approach. Define models for each table:

<code class="php">// User model
class User extends Model {
    public function shares() {
        return $this->hasMany('Share');
    }
    public function followers() {
        return $this->belongsToMany('User', 'follows', 'user_id', 'follower_id');
    }
}

// Share model
class Share extends Model {
    public function user() {
        return $this->belongsTo('User');
    }
}</code>

Then, you can use the following query:

<code class="php">$my = User::find('my_id');

// Eager load the owner of the share
$shares = Share::with('user')
    ->join('follows', 'follows.user_id', '=', 'shares.user_id')
    ->where('follows.follower_id', '=', $my->id)
    ->get('shares.*');

foreach ($shares as $share) {
    echo $share->user->username;
}</code>

This query retrieves all shares by users that you follow and eagerly loads the users who shared them.

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