Book Image

SQL Query Design Patterns and Best Practices

By : Steve Hughes, Dennis Neer, Dr. Ram Babu Singh, Shabbir H. Mala, Leslie Andrews, Chi Zhang
5 (1)
Book Image

SQL Query Design Patterns and Best Practices

5 (1)
By: Steve Hughes, Dennis Neer, Dr. Ram Babu Singh, Shabbir H. Mala, Leslie Andrews, Chi Zhang

Overview of this book

SQL has been the de facto standard when interacting with databases for decades and shows no signs of going away. Through the years, report developers or data wranglers have had to learn SQL on the fly to meet the business needs, so if you are someone who needs to write queries, SQL Query Design and Pattern Best Practices is for you. This book will guide you through making efficient SQL queries by reducing set sizes for effective results. You’ll learn how to format your results to make them easier to consume at their destination. From there, the book will take you through solving complex business problems using more advanced techniques, such as common table expressions and window functions, and advance to uncovering issues resulting from security in the underlying dataset. Armed with this knowledge, you’ll have a foundation for building queries and be ready to shift focus to using tools, such as query plans and indexes, to optimize those queries. The book will go over the modern data estate, which includes data lakes and JSON data, and wrap up with a brief on how to use Jupyter notebooks in your SQL journey. By the end of this SQL book, you’ll be able to make efficient SQL queries that will improve your report writing and the overall SQL experience.
Table of Contents (21 chapters)
1
Part 1: Refining Your Queries to Get the Results You Need
6
Part 2: Solving Complex Business and Data Problems in Your Queries
11
Part 3: Optimizing Your Queries to Improve Performance
14
Part 4: Working with Your Data on the Modern Data Platform

Using Common Table Expressions

Common Table Expressions (CTEs) are a powerful way to compartmentalize and organize your complex queries into bite-sized chunks that you can then manipulate the final output required by your process. CTEs can also be used to create recursive/hierarchal relationships to report on common parent/child scenarios, such as manager/employee.

In this chapter, we will learn how to use CTEs as one of the techniques to solve complex business and data problems. We’ll cover the best practices for creating and organizing CTEs, creating recursive queries for use in hierarchies, and reviewing other situations where CTEs can be used.

We are going to cover the following main topics in this chapter:

  • Creating CTEs
  • Using CTEs in recursive relationships
  • Recursive alternatives for Synapse

By the end of this chapter, you will understand why CTEs are important for query creators, how to create and use them, and how to utilize them to create...