How to Efficiently Select from Subqueries Using Laravel's Query Builder?

Select data from subqueries using the Laravel query builder

Question: Retrieving the value of a count aggregate from a SQL subquery using Eloquent ORM.

Initial method:

<code class="language-php">$sql = Abc::from('abc AS a')
    ->groupBy('col1')
    ->toSql();

$num = Abc::from(\DB::raw($sql))
    ->count();</code>

This approach requires manual generation of subquery SQL, which is not ideal.

Best solution:

The Laravel query builder currently lacks a dedicated method for creating subqueries in the FROM clause. Raw statements must be used manually, with proper binding management:

<code class="language-php">// 定义子查询
$sub = Abc::where(...)->groupBy(...); // Eloquent Builder 实例

// 创建主查询
$count = DB::table(DB::raw("({$sub->toSql()}) AS sub"))
    ->mergeBindings($sub->getQuery()) // 正确合并绑定
    ->count();</code>

Note: Bindings must be merged in the correct order. If additional conditions are added after merging, the order must be adjusted to ensure correct binding.

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