Row num instead of db ID ?

Just derive a row number field. I am guessing it is just for looks. But you don't need to show the id field anyway, just skip that field in a foreach, can still be part of the query.

you can try

$loop->index + 1

https://laravel.com/docs/5.7/blade#the-loop-variable

I tried defining resource field like this:

Text::make('#', function () {
    return view('partials.rownum')->render();
})->asHtml(),

And in the 'partials/rownum.blade.php' I put {{ $loop->index + 1 }}, but the page returns error: Undefined variable: loop;

Is there any way I could hook into index table foreach loop, or is it accessible just within frontend Vue component?

Is it maybe possible to override indexQuery(NovaRequest $request, $query) and to somehow append row num column to the query?

In case someone needs this, I've managed to solve this by using MySql's query session variables feature explained here.

First you have to override indexQuery method like this:

...
use Illuminate\Support\Facades\DB;
...

public static function indexQuery(NovaRequest $request, $query)
{
        // Needed for proper row nums when using pagination
        $offset = $request->input('perPage', 0) * ($request->input('page', 1) - 1); 

        DB::statement(DB::raw('set @row_number = 0'));

        return $query->select([
                DB::raw("(@row_number:=@row_number + 1) + $offset AS num"),
                'your_table_name.*'
        ]);
}

Then, define 'rownum' field in resource $fields array:

Text::make('#', 'num')->sortable()

That's it.

@electrobuddha @siangboon was meaning in a for/foreach loop in blade while displaying the data. $loop only exists within a blade loop. instead of using index + 1 you can just use iteration, which starts at 1 instead of 0 for the loop count so it wouldn't need to be manually incremented.

@foreach ($collections as $collection)
    {{ $loop->iteration }}  // starts at 1

    {{ $collection->name }}
    {{ $collection->description }}
@endforeach

@CRONIX - This is Laravel Nova related, there are no blade templates here (when rendering resource index page).

@electrobuddha I didn't say there was. I was clarifying what he was meaning and that $loop only exists within blade loops. You were getting an error when using $loop. I was stating why.

Sorry to bump a 3 year old post but since this is the #1 result on google for this search, I wanted to post an updated solution without touching the indexQuery since we have many other uses for indexQuery.

This solution handles pagination as well

 /**
     * Get the fields displayed by the resource.
     *
     * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
     * @return array
     */
    public function fields(NovaRequest $request)
    {
        if (!$request->count) {
            $request->count = 0;
        }
        return [
            Text::make('#', function () use ($request) {
                $request->count += 1;
                $rowNumber = $request->page == 1 ? $request->count : $request->count + ($request->perPage * ($request->page - 1));
                return $rowNumber;
            })->asHtml()->textAlign('center')->onlyOnIndex(),
        ];
    }