Articles Cookbook
24 Mar 2022
Tihomir Babic

How to Write Multiple CTEs in SQL

In this article, I will show you how to leverage the power of multiple CTEs (Common Table Expressions) by combining two or more in a single SQL query. I’ll explain how this technique can simplify complex queries, improve readability, and enhance efficiency when working with large datasets. Common table expressions, or CTEs, can be a powerful SQL tool. When you write two (or even more) CTEs together, this power multiplies.
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22 Mar 2022
Tihomir Babic

The SQL Substring Function in 5 Examples

Working with text data in SQL? We explain how to get values from any point in a string. When you think of working with data in SQL, your first thought is probably a database full of numbers and your SQL code doing very fancy calculations. But text is data, too! It’s very common to find text data in databases. Not only do you have to extract it, but often you also have to manipulate it.
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15 Mar 2022
András Novoszáth

SQL and Cloud Databases Are the Perfect Match!

Do you want to do analytics in the cloud? Are you considering learning SQL and wondering whether you can use it with cloud-based databases? Do you want to know how cloud databases and SQL work together? We answer your questions in this article. Read on! You may be an analyst who has heard about cloud databases and SQL and want to learn more. Maybe you are already familiar with them and want to know if the two technologies fit together.
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10 Mar 2022
Marcin Koryszewski

These Are the Websites You Should Know When Learning SQL

If you're diving into SQL and searching for top-notch resources to enhance your learning, you've arrived at the right article. Discover the ultimate SQL learning websites that we’ve carefully chosen to support your educational journey. Today, I'm going to share a list of websites that will help you with learning SQL. You will find useful resources, get introduced to some fantastic communities, and expand your database knowledge. Visit these sites regularly – ideally, every day.
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8 Mar 2022
Himanshu Kathuria

What Is the OUTER JOIN in SQL?

Even if you are new to SQL, you must have come across the term OUTER JOIN. In this article, I will explain what OUTER JOIN in SQL does. I’ll use some practical examples to demonstrate how it is used in day-to-day SQL applications. If you want to use SQL for practical purposes, learning the different JOINs is extremely important. In fact, you will be using a JOIN in just about every second query you write.
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24 Feb 2022
Jakub Romanowski

New MySQL Courses Are Here!

A lot of you have been waiting for new MySQL courses on LearnSQL.com – and finally, they’re here! Now you can learn everything MySQL in a simple, understandable, and fun way. We've worked a lot with these online SQL courses and created hundreds of interactive exercises to help you learn this popular SQL dialect. If you want to communicate with the world’s most popular open-source database, our MySQL courses will help you achieve that goal!
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23 Feb 2022
LearnSQL.com Team

Monthly SQL Practice in 2022 & 2021 Compilation Courses

Are you looking for ways to practice SQL? Tired of boring exercises based on unreal scenarios? We have something for you! Every month, we publish a new set of SQL practice exercises. You'll find all of them in the monthly SQL Practice. Here at LearnSQL.com, we believe the best way to learn SQL is through practice. All of our SQL courses (and there are over 30 of them!) are hands-on.
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22 Feb 2022
Dominika Florczykowska

An Overview of MySQL Data Types

What data types are available in a MySQL database? In this article, you’ll learn about numeric data types, text data types, and much more! You may have seen our article about data types in SQL. Here, we focus on the MySQL data types. We will discuss the most commonly used ones: numeric, text, and date and time. If you are interested in the topic, be sure to check out our Data Types in SQL course.
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15 Feb 2022
Kateryna Koidan

How to Keep Unmatched Rows From Two Tables in a SQL JOIN

Are you looking to join two tables in SQL without removing unmatched rows? Do you want to keep unmatched rows from one or both tables? In this article, I’ll explain how to keep all the records you want by using outer JOINs, such as LEFT JOIN, RIGHT JOIN, and FULL JOIN. Examples included! The SQL JOIN is a powerful tool that helps you combine data from multiple tables of your database.
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10 Feb 2022
Tihomir Babic

How to Query a Parent-Child Tree in SQL

What are parent-child tree structures in SQL? In this article, we answer that question, talk about query hierarchy, and demonstrate the five most common SQL queries you’ll need for these data structures. Yes, you can use SQL on a parent-child tree structure. I’ll show you how in this article. Along the way, I’ll walk you through five query examples, starting with the easiest and ending with the most complex.
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