在laravel获得下一个和上一个条目

Question

I'm trying to get the next and previous items (title and image) for each topic and I have this for next and previous links:

$currentUser = PostTranslation::find($post->id);

$previousUserID = PostTranslation::where('id', '<', $currentUser->id)->max('id');

$nextUserID = PostTranslation::where('id', '>', $currentUser->id)->min('id');

but it's just get the next and previous link id, which I need to get the title for them too. I have used this:

$previousUserID2 = PostTranslation::find($currentUser->id-1);

but it's when id = 0 that I am getting an error.

Answer 1

If your dataset is too big max and min can slow down your sql.

You can use first along with orderby which retrieve the first model matching the query constraints.

   $currentUser = PostTranslation::find($post->id);
   //order by descending order and take the first entry
   $previousUser = PostTranslation::where('id', '<', $currentUser->id)->select('id','title')->orderby('id','desc')->first();
   $previous_id=$previousUser ->id;
   $previous_title=$previousUser ->title;
   //order by ascending order and take the first entry
   $nextUser = PostTranslation::where('id', '>', $currentUser->id)->select('id','title')->orderby('id','asc')->first();
   $next_id=$nextUser ->id;
   $next_title=$nextUser ->title;

Answer 2

That's last code i have been used at my controller :

$previousUser = PostTranslation::join('posts', 'posts.id', '=', 'post_translations.post_id')
        ->where('posts.id', '<', $currentUser->id)
        ->select('posts.id','post_translations.title','post_image')
        ->orderby('posts.id','desc')
        ->where('post_translations.language', $language)
        ->first();