code: public function quoteSimpleColumnName($name)
      {
          if (is_string($this->tableQuoteCharacter)) {
              $startingCharacter = $endingCharacter = $this->columnQuoteCharacter;
          } else {
              list($startingCharacter, $endingCharacter) = $this->columnQuoteCharacter;
          }
          return $name === '*' || strpos($name, $startingCharacter) !== false ? $name : $startingCharacter . $name . $endingCharacter;
      }
docs: Quotes a simple column name for use in a query.
  A simple column name should contain the column name only without any prefix.
  If the column name is already quoted or is the asterisk character '*', this method will do nothing.
  @param string $name column name
  @return string the properly quoted column name