code: public Optional<String> getAlias(final String name) {
          if (containStar) {
              return Optional.absent();
          }
          String rawName = SQLUtil.getExactlyValue(name);
          for (SelectItem each : items) {
              if (SQLUtil.getExactlyExpression(rawName).equalsIgnoreCase(SQLUtil.getExactlyExpression(SQLUtil.getExactlyValue(each.getExpression())))) {
                  return each.getAlias();
              }
              if (rawName.equalsIgnoreCase(each.getAlias().orNull())) {
                  return Optional.of(rawName);
              }
          }
          return Optional.absent();
      }
docs: Get alias.
  
  @param name name or alias
  @return alias