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  3. Data-Driven Decision Making in SQL
  • 1

    Introduction to business intelligence for a online movie rental database

    Free

    The first chapter is an introduction to the use case of an online movie rental company, called MovieNow and focuses on using simple SQL queries to extract and aggregated data from its database.

  • 2

    Decision Making with simple SQL queries

    More complex queries with GROUP BY, LEFT JOIN and sub-queries are used to gain insight into customer preferences.

  • 3

    Data Driven Decision Making with advanced SQL queries

    The concept of nested queries and correlated nested queries is introduced and the functions EXISTS and UNION are used to categorize customers, movies, actors, and more.

  • 4

    Data Driven Decision Making with OLAP SQL queries

    The OLAP extensions in SQL are introduced and applied to aggregated data on multiple levels. These extensions are the CUBE, ROLLUP and GROUPING SETS operators.

Initializing

Exercise

Examining annual rentals

You are asked to provide a report about the development of the company. Specifically, your manager is interested in the total number of movie rentals, the total number of ratings and the average rating of all movies since the beginning of 2019.

Instructions 1/4

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  • First, select all records of movie rentals since January 1st 2019.