Laravel 5.2 - Delete duplicates from my query - php

Question

i have a query like this:
$players = PostBalance::where('post_id', $post->id)->orderBy('id','desc')->get();
It work well and return array with all values, Post balances have fields:
ID
score
post_id
user_id
I would like Delete user_id duplicated AND get the max score value. for example if i have:
[0] = 'id' => 1 , 'score'=> 10, 'user_id'=> 1, 'post_id' => 1
[1] = 'id' => 2 , 'score'=> 20, 'user_id'=> 1, 'post_id' => 1
[2] = 'id' => 3 , 'score'=> 30, 'user_id'=> 1, 'post_id' => 1
[3] = 'id' => 4 , 'score'=> 40, 'user_id'=> 2, 'post_id' => 1
[4] = 'id' => 5 , 'score'=> 50, 'user_id'=> 2, 'post_id' => 1
[5] = 'id' => 6 , 'score'=> 60, 'user_id'=> 2, 'post_id' => 1
I would like delete duplicates user_id and get only the user_id with max score:
RESULT:
[0] = 'id' => 3 , 'score'=> 30, 'user_id'=> 1, 'post_id' => 1
[1] = 'id' => 6 , 'score'=> 60, 'user_id'=> 2, 'post_id' => 1

Answer 1

You can use groupBy() and max() method like this (note: this will not actually delete the duplicates from DB, but work for your query):
$result = PostBalance::groupBy('user_id')
->max('score');
For further reference, see Laravel Docs
Or if you want to order the results by score, you can do it like this:
$result = PostBalance::orderBy('score', 'desc')
->groupBy('user_id')
->get();
Note: To get max of group by, try to first run orderBy(), then run groupBy() on the query instead.
Hope this helps!