laravel，用不同的过滤器过滤多对多的关系

Question

I'm building a website with laravel. I use these models:

• Post
• Countrytag
• Citytag
• Categorytag

A post can have many countrytags , citytags or categorytags and vice versa.

I would like to search posts by tags.

I use this function:

    public function blogsearchresults(Request $request)
        {   
            $attributes=request()->validate([

                'countrytag_id'=>'required_without_all:citytag_id,categorytag_id',
                'citytag_id'=>'required_without_all:countrytag_id,categorytag_id',
                'categorytag_id'=>'required_without_all:countrytag_id,citytag_id'
            ]);
            $posts=Post::all();
            if($request->has('countrytag_id')) {
                $countryid=$attributes['countrytag_id'];
                $posts =$posts->whereHas('countrytags', function ($query) use ($countryid){
                $query->wherein('countrytag_id', $countryid); 
                });
            }
            if($request->has('citytag_id')) {
                $cityid=$attributes['citytag_id'];
                $posts=$posts->whereHas('citytags', function ($query2) use ($cityid){
                $query2->wherein('citytag_id', $cityid); 
                });
            }
            if($request->has('categorytag_id')) {
                $categoryid=$attributes['categorytag_id'];
                $posts=$posts->whereHas('categorytags', function ($query3) use ($categoryid){
                $query3->wherein('categorytag_id', $categoryid);  
                });
            }        
            $posts=$posts->paginate();

            return view('pages.blog.blogsearchresults', compact('posts'));

        }

But I get this error:

Method Illuminate\Database\Eloquent\Collection::whereHas does not exist.

Could you please help me in solving this issue? Thank you

Answer 1

the method all() returns a collection, you can't use query builder methods on it. (also when you query build, you dont need to assign the value $posts over and over)

public function blogsearchresults(Request $request)
    {   
        $attributes = request()->validate([

            'countrytag_id'=>'required_without_all:citytag_id,categorytag_id',
            'citytag_id'=>'required_without_all:countrytag_id,categorytag_id',
            'categorytag_id'=>'required_without_all:countrytag_id,citytag_id'
        ]);
        $postQuery = Post::query();
        if($request->has('countrytag_id')) {
            $countryid = $attributes['countrytag_id'];
            $postQuery->whereHas('countrytags', function ($query) use ($countryid){
            $query->wherein('countrytag_id', $countryid); 
            });
        }
        if($request->has('citytag_id')) {
            $cityid = $attributes['citytag_id'];
            $postQuery->whereHas('citytags', function ($query2) use ($cityid){
            $query2->wherein('citytag_id', $cityid); 
            });
        }
        if($request->has('categorytag_id')) {
            $categoryid = $attributes['categorytag_id'];
            $postQuery->whereHas('categorytags', function ($query3) use ($categoryid){
            $query3->wherein('categorytag_id', $categoryid);  
            });
        }        
        $posts = $postQuery->paginate();

        return view('pages.blog.blogsearchresults', compact('posts'));

    }