JOIN query and GROUP BY .py

# Single query with join and group by
sql_str = """
SELECT 
  category, 
  avg(sentiment_polarity) as avg_sentiment_polarity, 
  avg(sentiment_subjectivity) as avg_sentiment_subjectivity
FROM (
  SELECT 
    category, 
    CAST(sentiment as float) as sentiment, 
    CAST(sentiment_polarity as float) as sentiment_polarity
  FROM gstore_apps_df 
    INNER JOIN gstore_reviews_df
    ON gstore_apps_df.app = gstore_reviews_df.app
) sub
GROUP BY category
HAVING avg_sentiment_subjectivity < 0.5
ORDER BY avg_sentiment_polarity DESC
LIMIT 10
"""

# Run query using apps and reviews dataframes, 
# NOTE: that you simply pass the names of the tables in the query as arguments

result_df = mdsql.query( sql_str, 
                        gstore_apps_df = gstore_apps_df, 
                        gstore_reviews_df = gstore_reviews_df)