How to create a query in Drupal 8

Question

I am used to using db_select in drupal 7 but now it's deprecated in drupal 8

So, If I need to create a query to list all users from users_field_data table, What should I do?

Do I still use db_select or db_query even though they are deprecated functions? Or create a new controller to extend from "Select class" and make my query?

Answer 1

As mentioned in the documentation you can query data by injecting Drupal's database connection class. For example:

use Drupal\Core\Database\Connection;

class DatabaseQueryExample {

  protected $connection;

  public function __construct(Connection $connection) {
    $this->connection = $connection;
  }

  public function queryExamples() {
    // db_query()
    $this->connection->query(" ... ");
    // db_select()
    $this->connection->select(" ... ");   
  }

}