Prefer to use Eloquent over raw SQL queries

Eloquent allows you to write readable and maintainable code. Also, Eloquent has great built-in tools like soft deletes, events, scopes etc.

Bad:

SELECT *
FROM `articles`
WHERE EXISTS (SELECT *
              FROM `users`
              WHERE `articles`.`user_id` = `users`.`id`
              AND EXISTS (SELECT *
                          FROM `profiles`
                          WHERE `profiles`.`user_id` = `users`.`id`) 
              AND `users`.`deleted_at` IS NULL)
AND `verified` = '1'
AND `active` = '1'
ORDER BY `created_at` DESC

Good:

Article::has('user.profile')->verified()->latest()->get();

Mass assignment

Bad:

$article = new Article;
$article->title = $request->title;
$article->content = $request->content;
$article->verified = $request->verified;
// Add category to article
$article->category_id = $category->id;
$article->save();

Good:

$category->article()->create($request->validated());

Do not execute queries in Blade templates and use eager loading (N + 1 problem)

Bad (for 100 users, 101 DB queries will be executed):

@foreach (User::all() as $user)
    {{ $user->profile->name }}
@endforeach

Good (for 100 users, 2 DB queries will be executed):

$users = User::with('profile')->get();

...

@foreach ($users as $user)
    {{ $user->profile->name }}
@endforeach

Chunk data for data-heavy tasks

Bad ():

$users = $this->get();

foreach ($users as $user) {
    ...
}

Good:

$this->chunk(500, function ($users) {
    foreach ($users as $user) {
        ...
    }
});

Prefer descriptive method and variable names over comments

Bad:

// Determine if there are any joins
if (count((array) $builder->getQuery()->joins) > 0)

Good:

if ($this->hasJoins())

Do not put JS and CSS in Blade templates and do not put any HTML in PHP classes

Bad:

let article = `{{ json_encode($article) }}`;

Better:

<input id="article" type="hidden" value='@json($article)'>

Or

<button class="js-fav-article" data-article='@json($article)'>{{ $article->name }}<button>