[9.x] Added rawValue to Database Query Builder (and Eloquent as wrapper)

[eusonlito]

Currently there are a method to get a existing column value from database called value, this PR adds the method rawValue to get a value from a SQL expression.

For example, get first and last year from trip table using the Trip Model.

$first = TripModel::orderBy('date_at', 'ASC')->rawValue('YEAR(`date_at`)');
$last = TripModel::orderBy('date_at', 'DESC')->rawValue('YEAR(`date_at`)');

Or full name from the user table:

$fullname = UserModel::where('id', $id)->rawValue('CONCAT(`first_name`, " ", `last_name`)');

I think that there are a lot of usage cases for this method :)

Regards!
Lito.

[eusonlito]

Thanks @taylorotwell 🙂