presto-parser/src/main/java/io/prestosql/sql/tree/Join.java/Join/toString
class Join:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("type", type)
                .add("left", left)
                .add("right", right)
                .add("criteria", criteria)
                .omitNullValues()
                .toString();
    }