How to optimize query statement in Laravel 7?

Question

I show code in the screenshot, because I want to show you guys my line 43

The actual code is here:

public function index()
{
    $inputs    = Request::all();
    $interval  = '';

    if(array_key_exists('interval', $inputs)){
        $interval  = $inputs['interval'];
    }

    switch ($interval) {
        case 'day':
        $visitors = Visitor::where('created_at', '>', now()->today())->paginate(20);;
        break;
        case 'week':
        $visitors = Visitor::where('created_at', '>', now()->subMonth())->paginate(20);;
        break;
        case 'month':
        $visitors = Visitor::where('created_at', '>', now()->subMonth())->paginate(20);;
        break;
        case 'year':
        $visitors = Visitor::where('created_at', '>', now()->subYear())->paginate(20);
        break;
        default:
        $visitors = Visitor::orderBy('updated_at', 'desc')->paginate(20);
        break;
    }

    return View::make('layouts.be.visitors.index', get_defined_vars());
}

I visit

http://app.test/visitor?interval=year

As you can see

Laravel Debugbar detected that I did 2 queries on line 43

Why 2? Is this expected?

Can I improve this into 1?

Please advise

Answer 1

second query is run by paginate() method.

If you look at this pagination response from laravel official documentation you will see one field called total . That's why that query runs to get total number of records:

{
   "total": 50,
   "per_page": 15,
   "current_page": 1,
   "last_page": 4,
   "first_page_url": "http://laravel.app?page=1",
   "last_page_url": "http://laravel.app?page=4",
   "next_page_url": "http://laravel.app?page=2",
   "prev_page_url": null,
   "path": "http://laravel.app",
   "from": 1,
   "to": 15,
   "data":[
        {
            // Result Object
        },
        {
            // Result Object
        }
   ]
}

That select count(*) as aggregate from visitors WHERE created_at > '2019-03-13 12:22:22 query runs automatically.

If you want to set it manually you have to use LengthAwarePaginator .

But I don't recomend to do that because of only one more query

See here about LengthAwarePaginator : https://github.com/laravel/ideas/issues/826

EDIT:

Here is how you can optimize your code:

use DB;
use Carbon\Carbon;
...
public function index()
{
    $inputs    = Request::all();
    $interval  = '';

    if(array_key_exists('interval', $inputs)){
        $interval  = $inputs['interval'];
    }

    $visitors = Visitor::when(in_array($interval, ['day', 'month', 'week', 'year']), function($q) use ($interval){
        return $q->where('created_at', '>', Carbon::parse("now -1 $interval"));
    }, function($q) {
        return $q->orderBy('updated_at', 'desc');
    })->paginate(20);

    return View::make('layouts.be.visitors.index', get_defined_vars());
}

See more about when method here: https://laravel.com/docs/7.x/queries#conditional-clauses

Hope this helps

Answer 2

It's because of the pagination object. You want to run the LIMIT, but still know how many rows would have been returned without the LIMIT. There is a way using mysql function FOUND_ROWS() but Laravel use the two queries way to count.