code: @Override
    public QueryBuilder<V> select(String columns) {
      Preconditions.checkNotNull(columns, "SELECT clause cannot be null");
      columns = removeKeyword(columns, SELECT);
      this.select = columns;
      return this;
    }
docs: Sets the statement SELECT clause in the form of "a,b" or "*".
  Only necessary for statements being sent to the
  {@code PublisherQueryLanguageService}. The "SELECT " keyword will be
  ignored.
  
  @param columns the statement select clause without "SELECT"
  @return a reference to this object