Laravel: how to use derived tables / subqueries in

2019-01-23 06:16发布

Edit:

Though this question originally was specific for the query I'm describing underneath, the answer I got applies to almost all questions related to using derived tables / subqueries in Laravel

Original Question:

Lately I'm a bit stuck on the laravel query builder. It has some really nice features but I feel like it just isn't build for more complex database operations.

This is the query I'm trying to build:

select 

'IFNULL(counted.product_count, 0) AS product_count', 
'uncounted.value', 
'uncounted.attribute_id', 
'uncounted.attribute_option_id' 

    from ( 

        select
        'counted.id', 
        'counted.attribute_id', 
        'counted.value', 
        'count(counted.attribute_id) AS product_count'

        from `attribute_options` as `counted` 
        where `counted.product_id` in (?, ?, ?, ?, ?) 
        group by `counted.attribute_option_id` 

    ) as 'counted' 

right join 'attribute_options' as 'uncounted'
        on 'counted.id' = 'uncounted.id' 

  group by 'attribute_option_id'

Explanation of the query: I'm building a faceted search for my product catalog in laravel. Products are narrowed down based on the filters/attributes users provide. For better user experience I want to show the amount of products left for each filter, that's what the query above does: counting all the products for a certain attribute WHERE the product_id is IN an array of product id's.

My try:

    $productIds = [ 1, 2, 3, 4, 5 ];

    $subQuery = \DB::table('attribute_options')->selectRaw('counted.id, counted.attribute_id, counted.value, count(counted.attribute_id) AS product_count')
                    ->from('attribute_options AS counted')
                    ->whereIn('counted.product_id', $productIds)
                    ->groupBy('counted.attribute_option_id')
                    ->mergeBindings($subQuery);

    $query = Model::selectRaw('IFNULL(counted.product_count, 0) AS product_count, uncounted.value, uncounted.attribute_id, uncounted.attribute_option_id')
                    ->from(\DB::raw(' ( ' . $subQuery->toSql() . ' ) AS counted '))
                    ->rightJoin('attribute_options AS uncounted', 'counted.id', '=', 'uncounted.id')
                    ->groupBy('attribute_option_id')
                    ->get();

Please help me because I don't like to use a DB::raw() or DB::select() statement. That wouldn't feel "Laravelish" or "Eloquent".

1条回答
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2楼-- · 2019-01-23 07:08

Your first try looks pretty close. Try this:

I removed the long namespace reference and suggest you add a use statement to make your code more readable

$productIds = [ 1, 2, 3, 4, 5 ];

$subQuery = DB::table('attribute_options AS counted')->selectRaw('counted.id, counted.attribute_id, counted.value, count(counted.attribute_id) AS product_count')
                ->whereIn('counted.product_id', $productIds)
                ->groupBy('counted.attribute_option_id')

$query = AttributeOption::selectRaw('IFNULL(counted.product_count, 0) AS product_count, uncounted.value, uncounted.attribute_id, uncounted.attribute_option_id')
                ->from(\DB::raw(' ( ' . $subQuery->toSql() . ' ) AS counted '))
                ->mergeBindings($subQuery->getQuery())
                ->rightJoin('attribute_options AS uncounted', 'counted.id', '=', 'uncounted.id')
                ->groupBy('attribute_option_id')
                ->get();
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