Some links about the topic from title
The Million Song Dataset Challenge aims at being the best possible offline evaluation of a music recommendation system
Do you want to query complex data structures in an iterative way? Do you have access to hierarchical data structures that need to be queried? This course will teach you the tools required to solve these questions. You will learn how to write recursive queries and query hierarchical data structures. To do this, you will use Common Table Expressions (CTE) and the recursion principle on a wide variety of datasets. You will, for example, dig into a flight plan dataset and learn how to find the best and cheapest connection between two airports. After completing this course, you will understand the principle of recursion, and be able to identify and create hierarchical data models.
This article aims at showing good practices on how to retrieve data with SQL using practical examples on the data above. The following topics are covered:
- operations on columns
- most common joins
- aggregations and window functions
- tips to handle complex queries
Have you ever wondered about the differences between a subquery and a common table expression (CTE) in SQL? The concepts seem very similar, but knowing the difference – and when to use each one – will help you write efficient and readable queries.