This series focuses on the most frequent data science and analytical problems in the real-world, and aims at solving them with SQL. — UPDATES (To the original post): Links to queries on SQLFiddle have been removed. Future updates include links to Jupyter/IPython notebooks embedded with SQL. Most of the queries here are written in ANSI SQL. For execution, PostgreSQL 9.6 has been included alongside MySQL 5.6, to demonstrate features such as Window Functions…