code: public function column($column, $db = null)
      {
          if ($this->emulateExecution) {
              return [];
          }
  
          // TODO add support for orderBy
          return $this->executeScript($db, 'Column', $column);
      }
docs: Executes the query and returns the first column of the result.
  @param string $column name of the column to select
  @param Connection $db the database connection used to execute the query.
  If this parameter is not given, the `db` application component will be used.
  @return array the first column of the query result. An empty array is returned if the query results in nothing.