Articles Cookbook
13 Dec 2020
LearnSQL.com Team

SQL Scholarship Program 2020

2020 is slowly coming to an end. It was extremely difficult for everyone. We’ve therefore decided to end it with something positive. This Holiday, we want to help someone change their life. Learn SQL will fund 50 SQL Scholarships for people who cannot afford to learn SQL and who may find it helpful in a difficult situation. We’ll hand out our flagship track - SQL From A to Z - for FREE!
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11 Dec 2020
Martyna Sławińska

What is an SQL View?

A view is a well-known feature in SQL. It allows you to create a virtual table based on an SQL query referring to other tables in the database. A view stores an SQL query that is executed whenever you refer to the view. This is a convenient way to get the desired data because it is easier to run a query stored in a view than to type a query from scratch.
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9 Dec 2020
Andrew Bone

The Top 10 SQL JOIN Interview Questions with Answers

Have you ever wondered what SQL JOIN questions you might be asked in an interview? Do you feel prepared to answer them? This article covers the most common SQL JOIN interview questions and how to answer them. If you are applying for a job as a data analyst or software developer, you will likely be asked about your SQL JOIN knowledge. SQL JOIN clauses are a great topic for interviewers to quiz you on.
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8 Dec 2020
Agnieszka Kozubek-Krycuń

The History of SQL Standards

Has the SQL standard changed in the 30+ years it's been around? Absolutely! Learn about the journey from SQL-86 to modern SQL, today’s standard data language. SQL was created in the early 1970s by IBM. In 1974, Donald Chamberlin and Raymond Boyce published the article SEQUEL: A Structured English Query Language, which introduced SQL to the world. The article contained the BNF grammar (a detailed technical description of the language syntax) for the language, which IBM later thought was a mistake.
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4 Dec 2020
Jakub Romanowski

SQL Terms Beginners Should Know – Part 2

This is the second part of my list of essential SQL terms for beginners. In the first, you learned what a table, relational database, and query are. Now, it's time for more advanced database terms. But don't be afraid! I won’t crush you with scientific definitions. I will explain everything simply so that you can easily understand. If you want to review the basic SQL terms, see my previous article, SQL Terms Beginners Should Know.
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3 Dec 2020
Kateryna Koidan

How Do You Write a SELECT Statement in SQL?

SQL is a language to communicate with relational databases, and the SELECT statement is the first thing you’ll learn when you start using SQL. In this article, you’ll learn how to write SELECT statements, from the basics to more advanced. What Is SQL? SQL stands for “Structured Query Language.” It has a long history that started in the 1970s. Being the standard for communication with relational databases, it has maintained its popularity.
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2 Dec 2020
Agnieszka Kozubek-Krycuń

SQL Technologies Are More Common Than You Think

Where is SQL being used today? The answers might surprise you! (Hint: SQL technology is basically everywhere.) Is it worth learning SQL? After all, the language was created in the 1970s. Is it still relevant today? The list of technologies that support SQL is very long – and it’s growing. Read on to find out what kinds of programs use SQL. SQL in Databases Relational Databases = SQL Databases It’s no surprise that SQL is used in relational databases.
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1 Dec 2020
LearnSQL.com Team

Course of the Month: Customer Behavior Analysis in SQL

Do you run a business? Do you want to squeeze even more out of your data? Start by analyzing your customers' behavior using SQL! Throughout December, you can learn how to do it for free on LearnSQL.com! I asked Agnieszka Kozubek-Krycuń, Vertabelo's Chief Content Officer, about our December Course of the Month, Customer Behavior Analysis in SQL. Here's what she told me. Let's start with the basics: Why analyze customer behavior?
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27 Nov 2020
Ignacio L. Bisso

What Is a Foreign Key in SQL?

What does a foreign key do in SQL? Why would you need one? Learn the ABCs of foreign keys in five minutes. Foreign keys are a central concept in SQL databases; they allow us to enforce data consistency. Usually they work with primary keys to connect two database tables, like a virtual bridge. All SQL developers need to know what SQL foreign keys are, how they work, what data values are allowed in them, and how they’re created.
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26 Nov 2020
Kateryna Koidan

Aggregate Functions vs Window Functions: A Comparison

If you aren’t familiar with SQL’s window functions, you may wonder how they differ from aggregate functions. When should you use window functions? In this article, we’ll review window functions and aggregate functions, examine their similarities and differences, and see which one to choose depending on what you need to do. After you’ve tackled basic SQL, you’ll probably want to get into some of its more advanced functions. That’s great; these functions make reporting and analysis easier.
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