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Free Course of the Month: Write Functions in PostgreSQL

Why learn to write user-defined functions? I’ll explain in this article – and how you can learn for free during July 2023 with this  PostgreSQL course!

PostgreSQL is one of the most popular databases in the world. This is mainly due to its great functionality and the fact that it’s open source (i.e. free!). Postgres is fast, it runs on multiple systems, and it’s suitable for almost any application. If you need a relational database solution, choose PostgreSQL.

Even though PostgreSQL gives you enormous possibilities, sometimes you need a special SQL function for a very specific task. This is where user-defined functions come into play – which you can learn for free in our interactive Writing User-Defined Functions in PostgreSQL course. It’s our Course of the Month for July 2023.

Why are we giving this course away for free? We care about the development of our users. We have been offering them free online SQL courses for a long time. Each month, we choose one SQL course and give everyone full free access to it. In most cases, a month is enough time to learn the given SQL topic well.

We want to support you in your quest to improve your PostgreSQL skills. Do you want to reach the next level? Learning to write user-defined functions will help get you there!

Writing User-Defined Functions in PostgreSQL

How do you get this free PostgreSQL course?

  1. Create a free account or log in if you already have one.
  2. Start the course. You will have free access to its content until the end of the month.

What Are User-Defined Functions in PostgreSQL?

PostgreSQL is one of the  most popular databases in the world, which makes the ability to use Postgres frequently sought after by employers. For some background on this database management system, see Breaking With Filing Cabinets: The History of PostgreSQL.

In PostgreSQL, functions allow you to perform operations that would normally take several queries. In simple words, this means you'll get your results much faster. Who wouldn’t want that?

User-defined functions extend the functionality of PostgreSQL. Thanks to them, you can work with data more conveniently, improve the logic of your SQL queries, and allow other applications to reuse your database. If you use Postgres at all in your work, this will really come in handy.

Maybe you've been working with PostgreSQL for a while and have long wanted to learn how to create new functions. In previous versions of PostgreSQL (up to the 11th version), PostgreSQL user-defined functions were sometimes called stored procedures. To this day, some people use this term interchangeably with user-defined functions. So don't be surprised if you see the term "stored procedure" somewhere. It refers to a user-defined function in PostgreSQL.

What Will You Learn in This SQL Course?

Our great interactive PostgreSQL course consists of 94 interactive exercises you can do at your own pace, from anywhere, and at any time. Completing all of them takes about 20 hours. If you want to learn more effectively and faster, it is worth checking out the tips we have collected in these articles:

The Writing User-Defined Functions in PostgreSQL online course is divided into six parts:

  1. Introduction to User-Defined Functions – Get familiar with creating functions in PostgreSQL. Not sure if you're ready to take this awesome course? If at any point you get the feeling that it's too difficult, try our SQL Basics in PostgreSQL course first.
  2. Writing Functions in PostgreSQL – the Basics – Learn the basic syntax of implementing functions in PostgreSQL. You’ll also see which parameter types are supported in PostgreSQL functions.
  3. Writing Complex Functions in PostgreSQL – Start using much more complex statements in functions.
  4. Functions returning tables in PostgreSQL – Discover how you can return tables from functions in PostgreSQL.
  5. Function management – Learn how to create, remove, and rename functions in PostgreSQL.
  6. Final quiz – Check your knowledge of writing functions in PostgreSQL by implementing a simple Extract-Transform-Load (ETL) process.
Writing User-Defined Functions in PostgreSQL

This course, like all the courses at, is interactive. You’ll learn how to write user-defined functions by writing real SQL queries and solving real problems.

We created our platform to empower our users to learn SQL and give them the best hands-on experience. You will write PostgreSQL queries in our console and see how they work right away. If you make a mistake somewhere, you'll immediately see what you need to fix. Everything is interactive and you don't need to install anything – it all happens in your browser.

Many users write to us that they have never found such a comfortable way to learn SQL. Our courses are also used by large companies in their employee onboarding process; you can read how we helped thousands of Uber employees here.

Do you want to learn even more about PostgreSQL? This SQL course is part of our SQL from A to Z in the PostgreSQL track. There, you’ll find everything you need to become a PostgreSQL expert! Check it out!

Who Should Take This Course?

We created this PostgreSQL course for slightly more advanced database users who need to develop their PostgreSQL skills. Are you a PostgreSQL developer or aspiring database administrator (DBA) who wants to keep progressing? Write your own PostgreSQL functions and become a query Jedi.

The SQL course is also useful for students in computer science and database classes. Are you enrolled in a college or university and want to use See what we have prepared especially for you. And let your teachers know about it, too – they may want to use it in their classes.

Writing User-Defined Functions in PostgreSQL

After completing this online SQL course, you’ll receive a PDF certificate. You can publish it on your LinkedIn profile. Check out how easy it is to do so in our short guide.

Employers are looking for people who can work with advanced PostgreSQL. Maybe this is an idea for a new career? If so, you can start looking for job opportunities on one of these sites. And if you find something advertising your dream job, you should prepare yourself well for the interview. The following articles will help you:

Free SQL Course for July 2023: Writing User-Defined Functions in PostgreSQL

Now you know that you should learn advanced PostgreSQL topics and that is the best place to do it. What are you waiting for? Start our course today!

If you feel that you still lack the appropriate skills – or if you are just starting your adventure with SQL – start with SQL Basics in PostgreSQL. Also, read 5 Tips for You From a Senior SQL Data Analyst. Perhaps it will inspire you to develop and help you in your career!

Happy learning!