Dynamic eloquent query injecting is not working in laravel

Question

I'm trying to build dynamic query using form inputs like below :

 $query = new Doctor();

 if (!empty($request->input('city'))) {
    $city = $request->input('city');
    //Search for any thing like doctor name or last name
    $query->where('city_id', $city);
 }


  //Get doctor names result in collection type
  $col = $query->where('level','LIKE','%%')->orderBy($Order_By, $Sort_Type)->toSql();

Problem is the part which check city and inject city where clause into query is not working and what I get as a query is :

"select * from `doctors` where `level` LIKE ? order by `profile_views` desc"

if I change the logic and put city where clause in single line like :

 $col = $query->where('city_id', $city)->where('level','LIKE','%%')->orderBy($Order_By, $Sort_Type)->toSql();

The result of this query is :

"select * from `doctors` where `city_id` is null and `level` LIKE ? order by `profile_views` desc"

how can I make the first logic to work ?

Answer 1

$query = new Doctor();

creates a new Doctor, but you don't really want that. Instead:

$query = Doctor::query();

creates a new query against the Doctor model, which can then be extended with where() etc. stuff.