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Introduction to SQL and Its History

Welcome to the Foundations of SQL course! This course is designed for anyone who wants to level up their SQL skills, including but not limited to:

  • Data analysts
  • Business analysts
  • Software engineers who build relational databases
  • Data scientists
  • Analytically-minded product managers
  • Database administrators
  • …and more!

Whether you’re looking to advance your career in data analysis or engineering, mastering SQL has become a critical skill for modern-day technologies.

By the end of this course, you’ll be able to grok advanced SQL concepts and write complex queries for real-world problems. But before we jump into the details, let’s review the core ideas behind SQL and how it came to be so popular.

Already familiar with SQL and looking to level up your advanced querying skills? Feel free to skip the introductory lessons and jump into more complex topics later in the course, such as aggregations, common table expressions, and window functions.

History of SQL

Structured Query Language, or SQL, is a programming language that is used to manage and manipulate data stored in relational databases. It’s considered one of the most important skills for data analysts and data engineers, and it is used extensively in organizations of all sizes to store, manage, and analyze large amounts of data.

SQL was first developed in the 1970s by IBM researchers as a way to manage data in relational databases. Over the years, it has evolved to become an industry-standard language for database management, and it is now supported by many different relational database management systems, including MySQL, PostgreSQL, SQL Server, Oracle, and many others. Each of these systems offers slight variations of the SQL standard, which we’ll call out throughout this course when relevant.

At its core, SQL is a declarative language that allows you to express your data management needs in a clear and concise manner. Instead of specifying how to retrieve the data, SQL allows you to specify what you want to retrieve and let the database management system figure out the most efficient way to retrieve it. This makes SQL a powerful tool for data analysis and data retrieval.

SQL is widely used everywhere in real-life applications, including data warehousing, business intelligence, and online transaction processing. In these applications, SQL is used to extract data from large datasets and transform it into meaningful information that can be used to make informed business decisions.

For example, a data analyst may use SQL to query a large database of sales data to determine the average sales per month for a specific product, or a data engineer may use SQL to extract data from different sources and load it into a data warehouse for further analysis.

Consider the following simple example:

SQL
SELECT *
FROM sales
WHERE product = 'SQL Course'

This is a clear and concise expression of what we want to retrieve—without specifying how to retrieve it. The database management system determines the most efficient way to execute this query for us.

It’s worth noting that, in a world of constantly-evolving technologies, SQL has had a remarkably long lifespan and shows no signs of becoming less popular. Some would say this illustrates the Lindy effect, the tendency for popular technologies to continue being popular. In other words, SQL is a great skill to invest in today because it remains as popular as ever.

Let’s get started!

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