Best Places to Practice SQL JOINs Online

You’ve just started your journey with SQL and you’re not sure what a JOIN is or where to use it. Don’t worry! In this article, you will find out what JOINs are and where you can practice them online.

If you have just started learning SQL, you have a lot of topics to cover before you can call yourself a data professional. If you are serious about using SQL, you’ll have to understand JOIN – what it does, when you can use it, and what its different variants do.

But don’t panic just yet. Learning JOINs isn’t hard, and there are several places where you can practice SQL JOINs online. First, let’s quickly recap what JOINs are and how they work.

What Is an SQL JOIN?

As you learn SQL, there will be times when you need to know how to combine two or more tables. And that’s what JOINs are about.

Joining tables and getting data from more than one table is actually a basic concept in relational databases.

In a real-world database, there is never one huge table that contains all the data you could possibly need. Instead, data is stored in many smaller tables that describe just one thing, like customers or products. Any time you want to get information from multiple places, you should use JOINs. There are even times when you’ll need to join a table with itself.

There are few different types of JOINs:

• INNER JOIN
• LEFT JOIN
• RIGHT JOIN
• FULL OUTER JOIN

Each of them has a different purpose and will give you different results. You will not immediately be able to distinguish which type to use and when, but that’s normal. Everything will come with experience. And to get experience, you need to practice!

Where to Practice SQL JOINS Online

There are a lot of ways to practice SQL JOINs. First of all, choose a resource that matches your skill level. There are online courses that will guide you from the basics up to more advanced exercises. Experienced SQLers can use open-source databases and come up with their own JOIN ideas.

Let’s look at some ways you can learn and practice JOINs. We’ll start with the most basic level, one that’s for people who are very new to SQL.

1.  SQL Basics

This is a good course if you want to build a solid SQL foundation. It’s for people with no prior knowledge of programming, databases, or SQL.

First, you will learn how to write simple queries on a single table. Next, you will start to work with multiple tables. You’ll  begin by writing simple JOINs, and then you’ll work up to more complicated queries. You’ll understand the differences between various joining methods and when you should use each one.

There are 129 interactive exercises in this course. You get feedback immediately, and whenever you get lost, you can use a hint.

This course is the perfect start to learning SQL JOINs. It’s a friendly, safe environment to practice without any consequences (like messing up your company’s data). After completing all the lessons, you’ll be able to move to more advanced training.

2.  SQL JOINs course

Maybe you already know what SQL JOINs are. You may know the differences between INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN. You’re ready for more advanced SQL practice.

Our SQL JOINs online course is just the place to develop your skills. It covers all the main JOIN types in detail. You will learn how to:

• JOIN and select data from more than one table.
• Join many tables in a single query.
• Use LEFT JOIN, RIGHT JOIN, and FULL JOIN.
• Correctly filter data with different kinds of JOINs.
• Join a given table to itself (self-joins).
• Join tables on non-key columns.

We estimate it will take about ten hours to complete these 90 interactive exercises.

3.  Mastering SQL Table Joins from Scratch

This online course is available on the Udemy online learning platform. It is not the cheapest option, but you can sometimes find a great price reduction.

This course starts from scratch and gives you the opportunity to deepen your knowledge. Important: you will need to download and install an Oracle database management system to proceed with this training. (The Express Edition of Oracle Database is free.) The course is built on videos and is divided into 5 modules with 55 lectures. You will need at least 5 hours to complete it.

The course starts with a short overview of database theory and looks at how to install the database. The biggest part of the course is the final one, which contains 16 practical JOIN examples. They are explained by the teacher in the videos.

4.  W3 Resource

When you feel more confident in your SQL knowledge, you can start to find more self-directed learning options. For example, you can check w3resource’s SQL exercises, practices, and solutions.

W3 is an easy platform to use. There are over twenty exercises to complete; each one has a description, a code editor where you can type your answer, and the correct solution at the end.  Each exercise is explained step by step, so you can compare that solution with yours.

5.  DIY SQL JOIN Practice

Another way to grow your knowledge of SQL JOINs is by downloading free open-source data sets and trying your own JOIN queries. You can install PostgreSQL for free on your computer, find an open-source database, and come up with your own problems to solve.

When you have your own database to work with, your creativity is the only limit. You can discuss cases with other SQL users, write your ideas, and test the solutions. Every time you make a mistake, you’re actually gathering needed experience.

Another practice idea is to use the free LearnSQL.com cheat sheet. You see the syntax of different JOINs and use that to create your own queries. The cheat sheet covers JOIN conditions, NATURAL JOIN, RIGHT JOIN, LEFT JOIN, FULL JOIN, CROSS JOIN, and more.

Ready to Start Practicing SQL JOINs?

As you can see, there are a lot of places where you can find SQL JOIN exercises.

By repeating information and learning systematically, you can gain a lot of experience. Practice SQL JOINs in a way that’s most effective for you. Give yourself time and don’t be afraid to challenge yourself. Online learning gives you room to make mistakes, so profit from it.

Most importantly, start practicing SQL JOINs!