original_string: public function fetchColumn(
              string $sql,
              array $values = [],
              int $columnIndex = 0
      ): Sequence {
          return $this->fetchAll(
                  $sql,
                  $values,
                  \PDO::FETCH_COLUMN,
                  ['columnIndex' => $columnIndex]
          );
      }
code: public function fetchColumn(
              string $sql,
              array $values = [],
              int $columnIndex = 0
      ): Sequence {
          return $this->fetchAll(
                  $sql,
                  $values,
                  \PDO::FETCH_COLUMN,
                  ['columnIndex' => $columnIndex]
          );
      }
code_tokens: public function fetchColumn ( string $ sql , array $ values = [ ] , int $ columnIndex = 0 ) : Sequence { return $ this -> fetchAll ( $ sql , $ values , \ PDO :: FETCH_COLUMN , [ 'columnIndex' => $ columnIndex ] ) ; }
docstring: return a list with all rows from given result
  
  Allows to map the result into a list of values from one single column:
  <code>
  $userNames = $database->fetchColumn('SELECT username FROM users WHERE status = "blocked"');
  </code>
  
  @param   string  $sql          sql query to fetch data with
  @param   array   $values       map of values in case $sql contains a prepared statement
  @param   int     $columnIndex  number of column to fetch
  @return  \stubbles\sequence\Sequence
docstring_tokens: return a list with all rows from given result