Сreate SelectNew query modifier for use NEW Operator Syntax

[peter-gribanov]

NEW Operator Syntax

Using the NEW operator you can construct Data Transfer Objects (DTOs) directly from DQL queries.

• When using SELECT NEW you don't need to specify a mapped entity.
• You can specify any PHP class, it only requires that the constructor of this class matches the NEW statement.
• This approach involves determining exactly which columns you really need, and instantiating a data-transfer object that contains a constructor with those arguments.

class CustomerDTO
{
    public function __construct($name, $email, $city, $value = null)
    {
        // Bind values to the object properties.
    }
}

// SELECT NEW CustomerDTO(customer.name, email.email, address.city, SUM(orders.value)) FROM Customer customer JOIN customer.email email JOIN customer.address address JOIN customer.orders orders GROUP BY customer.id
$spec = Spec::andX(
    Spec::selectNew(
        CustomerDTO::class,
        Spec::field('name'),
        Spec::field('email', 'email'),
        Spec::field('city', 'address'),
        Spec::SUM(Spec::field('value', 'orders')),
    ),
    Spec::groupBy('id'),
);

// array of CustomerDTO
$users = $rep->match($spec);