Articles Cookbook
5 Nov 2021
Karolina Niewiarowska

How Can SQL Developers Remember Everything They Learn?

Are you at the beginning of your SQL journey? Congratulations, great choice! But you may find the knowledge you gain leaks with time. Find out what SQL developers do to remember everything they learn for a long time. If you learn SQL, the road to the expert level is long, winding, and bumpy. But don't worry – we've all been through it. You know perfectly well it's worth it. And if you don't already know, here are the reasons why you should start learning SQL NOW!
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3 Nov 2021
Andrew Bone

What Is the DELETE Statement in SQL?

This article will explain the use of the DELETE statement, one of the primary methods of removing existing records from your database. First we will run through the syntax, followed by some easy-to-understand examples. The DELETE statement in SQL is extremely useful. It allows you to remove any obsolete or “bad” data from your database tables. You should exercise caution when using the DELETE statement, as the operation is not reversible.
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2 Nov 2021
Jakub Romanowski

Free SQL Course of the Month – Window Functions in PostgreSQL

This is what distinguishes ordinary SQL users from professionals – SQL window functions! Would you like to practice them in PostgreSQL, on one of the best interactive SQL courses in the world, and pay nothing for it? Throughout November, you have access to the Window Functions in PostgreSQL course for FREE. You read it right: you won't pay a penny! What's the catch? Why would someone give you a free course?
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1 Nov 2021
LearnSQL.com Team

New Monthly SQL Practice for November 2021!

If you are a more advanced SQL user who is comfortable writing complex GROUP BY statements, you can check your knowledge with November’s SQL Practice. Every month on LearnSQL.com, you‘ll find a new challenge to solve. Maybe this is the first time you’ve come across our Monthly SQL Practices. LearnSQL.com offers one free SQL Practice each month: basic levels on even-numbered months and advanced levels on odd-numbered months. Each SQL Practice takes about an hour (or less!
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29 Oct 2021
Ignacio L. Bisso

What Is a Rolling Average and How Do You Compute It in SQL?

In this article, we will show three different examples of using SQL to calculate rolling averages. Learn this and you will take an important step in your SQL growth! A rolling average is a metric that allows us to find trends that would otherwise be hard to detect. It is usually based on time series data. In SQL, we calculate rolling averages using window functions. First, let’s talk about what rolling averages are and why they’re useful.
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28 Oct 2021
Jakub Romanowski

Top 5 Linux Distributions for SQL

The world is divided into Linux lovers and people who have never tried it before. Still working on Windows or macOS? Do you want to learn SQL? Do you know a large proportion of IT professionals use Linux? It's not a coincidence. But which Linux distribution should you choose for learning SQL? Here's my factsheet to help answer that question.   Linux Distribution: What Is It? What is a Linux distribution?
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27 Oct 2021
Kateryna Koidan

SQL Date and Time Functions in 5 Popular SQL Dialects

Are you confused by all the date and time functions used across different SQL dialects? In this article, I summarize the date and time data types used in PostgreSQL, Oracle, SQLite, MySQL, and T-SQL. I also provide examples with the key SQL date and time functions used across these dialects. It’s time to become date and time gurus! Do you want to calculate how often employees are running late for work?
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25 Oct 2021
LearnSQL.com Team

Monster Hunt – Halloween Promo

We need your help! Our office has been haunted by a bunch of terrifying monsters. Only you can beat them. The worst of the monsters controls them all. Are you scared, do you feel chills? This Halloween, we wanted to give you an unusual gift - a promo code that would give you an additional $20 discount on our All Forever Plan. This means that, along with other promotions, you could now pay only $169 to access all of our SQL courses!
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22 Oct 2021
Jakub Romanowski

New Window Functions Practice Set Is Here!

Have you learned the SQL window functions? Or maybe, you forgot when and how to use them correctly? Are you preparing for an advanced SQL job interview? You've come to the right place! This is the new Window Functions Practice Set. This is very good news for all SQL learners and database professionals who want to improve their skills. The LearnSQL.com Team is proud to present the new Window Functions Practice Set!
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21 Oct 2021
Himanshu Kathuria

The SQL Count Function Explained With 7 Examples

One of the most useful aggregate functions in SQL is the COUNT() function. If you are new to SQL and want to learn about the various ways to use the COUNT() function with some practical examples, this article is for you. The COUNT() function is one of the most useful aggregate functions in SQL. Counting the total number of orders by a customer in the last few days, the number of unique visitors who bought a museum ticket, or the number of employees in a department, can all be done using the COUNT() function.
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