Laravel using UNION in query builder

Question

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 

Solution 1

Looks like your models are using Ardent, not Eloquent:

...instance of LaravelBook\Ardent\Builder given, ...

And probably this might be a problem on Ardent, not Laravel.

Open an issue here: https://github.com/laravelbook/ardent.

EDIT:

Try to change use QueryBuilder instead of Eloquent:

Use this for QueryBuilder:

DB::table('tags')->

Instead of the Eloquent way:

Tag::

Solution 2

I know you mentioned wanting to use the query builder, but for complex queries that the builder might throw fits on, you can directly access the PDO object:

$pdo = DB::connection()->getPdo();

Comments

[Al_]

Hi, I've tried setting all three models to extend Eloquent not Ardent I I get a similar error: Argument 1 passed to Illuminate\Database\Query\Builder::mergeBindings() must be an instance of Illuminate\Database\Query\Builder, instance of Illuminate\Database\Eloquent\Builder given, called in E:\docs\Documents\Work\MGC\mgc_root\vendor\laravel\framework‌​\src\Illuminate\Data‌​base\Query\Builder.p‌​hp on line 898 and defined

[Antonio Carlos Ribeiro]

Are you using Laravel 4.0 or 4.1?

[Al_]

4.0 I believe, I'll try running a composer update to see if that helps

[Antonio Carlos Ribeiro]

Edited, might work using QueryBuilder. But this looks like a bug on Laravel.

[Al_]

I'm on 4.0 the composer.json file has : "laravel/framework": "4.0.*",, I've run a composer update. Guess I'll file a bug report, thanks.

[Antonio Carlos Ribeiro]

Did you saw my edit? Tested using QueryBuilder instead of Eloquent?

[Al_]

Hi, just noticed it. That does seem to work - strange! Is that a bug that should be reported do you think or should I close the bug request I opened on github. Thanks!!

[Antonio Carlos Ribeiro]

Keep it. There's a problem on Eloquen/QueryBuilder.

[Antonio Carlos Ribeiro]

No problem. Enjoy Laravel! :)

[lu cip]

I got the same issue, anyway this is because mergeBindings() function expect an instance of Illuminate\Database\Query\Builder instead of Ardent\Builder or Eloquent\Builder... as you said before. So DB::table('tags') can replace Tag just for variable $itemListTags sent to union() function. I said that because sometimes (as in my case) you need Eloquent or Ardent for the first object ( as $itemTags in this case ), and this can stay Eloquent or Ardent. Thanks for your answer.