Spark Notebook is a Scala-centric tool for interactive and reactive data science using Apache Spark.

This is an excellent tool for prototyping Scala/Spark code with SQL queries to analyze data (by data visualizations). It seems to have more advanced data visualizations (comparing to Apache Zeppelin), and seems rather focused on Scala, SQL and Apache Spark.

It can visualize the output of SQL queries directly as tables and charts (which Apache Zeppelin cannot yet).