Laravel 在查询构建器中使用 UNION
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Laravel using UNION in query builder
提问by Al_
I have an SQL query that works fine and I'm trying to convert into fluent::
我有一个运行良好的 SQL 查询，我正在尝试转换为 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:
这就是我到目前为止所掌握的流利，据我从文档和个人查询中可以看出，这一切似乎都是正确的，只是当我联合它们时，它会引发错误：
$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();
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):
我在运行它时收到以下错误（我还在模型上从 Ardent 切换回 Eloquent 以防有所不同 - 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
回答by Antonio Carlos Ribeiro
Looks like your models are using Ardent, not Eloquent:
看起来您的模型使用的是 Ardent，而不是 Eloquent：
...instance of LaravelBook\Ardent\Builder given, ...
And probably this might be a problem on Ardent, not Laravel.
这可能是 Ardent 的问题，而不是 Laravel。
Open an issue here: https://github.com/laravelbook/ardent.
在此处打开一个问题：https: //github.com/laravelbook/ardent。
EDIT:
编辑：
Try to change use QueryBuilder instead of Eloquent:
尝试更改使用 QueryBuilder 而不是 Eloquent：
Use this for QueryBuilder:
将此用于 QueryBuilder：
DB::table('tags')->
Instead of the Eloquent way:
而不是雄辩的方式：
Tag::
回答by Uze
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:
我知道您提到要使用查询构建器，但是对于构建器可能会抛出的复杂查询，您可以直接访问 PDO 对象：
$pdo = DB::connection()->getPdo();
