With SparkSQL Cassandra connector can a JDBC client tool (ie DBVisualizer, Tableau, Alteryx.etc) join 2 cassandra tables with SparkSQL?
All documentation I see refers to joinWithCassandraTable (which I assume only works in scala/java code or spark-shell but not a standard SQL client) https://github.com/datastax/spark-cassandra-connector
DSE should support this if you're using JDBC driver that is available from DataStax Academy Downloads page. You'll need to run the Spark SQL Thrift server (via dse spark-sql-thriftserver command)... If you're just starting, DSE 6 has more improvements around this part (so-called Always On SQL Service (AOSS)).
Here is the old blog post that talks about ODBC driver + Spark SQL and joins, but the same should be for JDBC drivers.