Laravel在查询构建器中使用UNION(Laravel using UNION in query builder)

 我有一个SQL查询工作正常，我正在尝试转换为流利:: 
 
SELECT DISTINCT tags.tag
  FROM tags, items
  WHERE tags.taggable_type = 'Item'
  AND items.item_list_id = '1'
UNION
SELECT DISTINCT tags.tag
  FROM tags, itemlists
  WHERE tags.taggable_type = 'ItemList'
  AND itemlists.id = '1'
 
 这是我到目前为止流利的，从文档中可以看出这一切似乎是正确的，并且各个查询都是自己工作的，只是当我联合它们时它会抛出一个错误： 
 
   $itemTags = Tag::join('items', 'items.id', '=', 'tags.taggable_id')
                ->select('tags.tag')
                ->distinct()
                ->where('tags.taggable_type', '=', 'Item')
                ->where('items.item_list_id', '=', $itemList->id);

    $itemListTags = Tag::join('itemlists', 'itemlists.id', '=', 'tags.taggable_id')
                ->select('tags.tag')
                ->distinct()
                ->where('tags.taggable_type', '=', 'ItemList')
                ->where('itemlists.id', '=', $itemList->id);
// the var_dump below shows the expected results for the individual queries
// var_dump($itemTags->lists('tag'), $itemListTags->lists('tag')); exit;
    return      $itemTags
                ->union($itemListTags)
                ->get();
 
 当我运行它时，我得到以下错误（我也在模型上从Ardent交换回Eloquent，以防有所作为 - 它没有）： 
 
Argument 1 passed to Illuminate\Database\Query\Builder::mergeBindings() must be an instance of Illuminate\Database\Query\Builder, instance of LaravelBook\Ardent\Builder given, called in path/to/root\vendor\laravel\framework\src\Illuminate\Database\Query\Builder.php on line 898 and defined 

I have an SQL query that works fine and I'm trying to convert into fluent::
 
SELECT DISTINCT tags.tag
  FROM tags, items
  WHERE tags.taggable_type = 'Item'
  AND items.item_list_id = '1'
UNION
SELECT DISTINCT tags.tag
  FROM tags, itemlists
  WHERE tags.taggable_type = 'ItemList'
  AND itemlists.id = '1'
 
This is what I have so far in fluent, it all seems right as far as I can tell from the docs and the individual queries both work on their own, it's just when I UNION them it throws an error:
 
   $itemTags = Tag::join('items', 'items.id', '=', 'tags.taggable_id')
                ->select('tags.tag')
                ->distinct()
                ->where('tags.taggable_type', '=', 'Item')
                ->where('items.item_list_id', '=', $itemList->id);

    $itemListTags = Tag::join('itemlists', 'itemlists.id', '=', 'tags.taggable_id')
                ->select('tags.tag')
                ->distinct()
                ->where('tags.taggable_type', '=', 'ItemList')
                ->where('itemlists.id', '=', $itemList->id);
// the var_dump below shows the expected results for the individual queries
// var_dump($itemTags->lists('tag'), $itemListTags->lists('tag')); exit;
    return      $itemTags
                ->union($itemListTags)
                ->get();
 
I get the following error when I run it (I've also swapped from Ardent back to Eloquent on the model in case that made a difference - it doesn't):
 
Argument 1 passed to Illuminate\Database\Query\Builder::mergeBindings() must be an instance of Illuminate\Database\Query\Builder, instance of LaravelBook\Ardent\Builder given, called in path/to/root\vendor\laravel\framework\src\Illuminate\Database\Query\Builder.php on line 898 and defined 

原文：https://stackoverflow.com/questions/19050387