How can i query by user input?

What does it mean "this code is not work"? We need more details

Oh~ I mean in Laravel seems you must use $result = Product::where(...)->orderBy(...)->get(); to query data , it work fine.

but you can't create a object at first like $result = new Product(); and call $result->where()->get(); later , that will get no result.

if there any way to do i can create a object first and call where()->get() later?

If you are fairly new to laravel, you could use the tutorial that ver 5.2 had, code is also on Github: https://laravel.com/docs/5.2/quickstart-intermediate

https://github.com/laravel/quickstart-intermediate

It's a pretty good into tutorial from Taylor. And many of Jeffrey's tutorials are free.

Replace

if($catgory_id ){
        $ps = Category::find($catgory_id )->products()->where('status', 1);
    }else{
        $ps = Product->where('status', 1);
    }

    if($keyword){
        $ps->andWhere(function($query){
            $query->where('name','like','%'.$keyword.'%')
            ->orWhere('introduce','like','%'.$keyword.'%')
            ->orWhere('itemid','like','%'.$keyword.'%');
        });
    }
    
    $ps->orderBy('created_at', 'desc')->paginate(20);

with

if($catgory_id ){
        $ps = Category::find($catgory_id )->products()->where('status', 1);
    }else{
        $ps = Product->where('status', 1);
    }

    if($keyword){
        $ps =$ps->andWhere(function($query){
            $query->where('name','like','%'.$keyword.'%')
            ->orWhere('introduce','like','%'.$keyword.'%')
            ->orWhere('itemid','like','%'.$keyword.'%');
        });
    }
    
    $ps =$ps->orderBy('created_at', 'desc')->paginate(20);