DruidJoinQueryRel for pydruid

[rooom13]

Which is the equivalent for a DruidJoinQueryRel on pydruid?

DruidJoinQueryRel java reference: https://github.com/apache/druid/blob/master/sql/src/main/java/org/apache/druid/sql/calcite/rel/DruidJoinQueryRel.java

I would like to execute multiple queries on parallel via a single druid query. This can be achieved by a SQL query like:

SELECT f_cnt, f_vol FROM
  (SELECT sum("vol") as "f_vol" FROM "A"),
  (SELECT sum("count") as "f_cnt"  FROM "B")

Which is translated to native druid query as

DruidJoinQueryRel (joinType) & 2 sub queries DruidQueryRel

But there is no such join query on the pydruid client

Or any other suggestion for executing multiple queries on a single druid query?