Articles Cookbook

How to Publish a LearnSQL.com Course Certificate on LinkedIn

by Jakub Romanowski
25 Jun 2020 LinkedIn draws both job seekers and recruiters. Showcasing your knowledge, skills, and experience on this professional networking site can lead to great opportunities. We know this well at LearnSQL.com. Have you finished one of our courses? Great! Tell your future employer about what you have learned. Here's a step-by-step how-to guide for publishing a course certificate on LinkedIn. I will show you how easy it is to publish a LearnSQL.
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TRUNCATE TABLE vs. DELETE vs. DROP TABLE: Removing Tables and Data in SQL

by Dorota Wdzięczna
24 Jun 2020 What’s the difference between truncating, deleting, and dropping a table in SQL? Find out in this article. There are a lot of ways to delete data in SQL, including the DELETE, TRUNCATE TABLE and DROP TABLE commands. Which one should you use in a given situation? In this article, you’ll learn the syntax of each command in different database engines like MySQL, PostgreSQL, SQL Server, and Oracle. And you’ll understand the DROP TABLE vs.
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How to Learn the SQL Syntax

by Kate Stolarek
23 Jun 2020 Read about what SQL is, and choose the best way for you among a wide variety of possibilities for learning SQL and remembering its syntax. What Is SQL? “SQL” stands for “Structured Query Language,” and as it sounds, it is a language dedicated to querying a relational database. In practice, it is used for creating, designing, and managing a relational database. People use SQL to: Create sets of tables and rows Modify database tables and index structures Insert, update, and delete data Retrieve information from a database for a variety of uses such as analytics Relational databases consist of a set of tables containing rows and columns of data.
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A Mathematician in the World of SQL

by Jakub Romanowski
18 Jun 2020 She has a PhD in Mathematics and over 10 years’ experience teaching mathematics and computer science at the University of Warsaw. She knows SQL better than just about anyone I’ve met. Let’s get to know Agnieszka Kozubek-Krycuń, Vertabelo’s Chief Content Officer at Vertabelo. Let's go back in time. How did your adventure with math start? I’ve always enjoyed abstract concepts and problem solving. I was fascinated by variables when we learned to solve simple equations like x+2=5 in primary school.
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Last-Minute Preparation Tips for a Database Class Exam

by Adrian Więch
17 Jun 2020 Getting to learn SQL is fun. You don’t really need to spend much time to understand some basic SQL concepts and use them fluently. If you’re a student facing your first database class exam soon, we’ve got you covered. In this article, we explain what you should focus on while learning SQL and studying for an entry-level database exam. Check your knowledge with our 10 sample questions and discover where you can find more SQL practice.
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How to Practice SQL Window Functions at Home

by Tihomir Babic
16 Jun 2020 Are you looking for a way to maintain your knowledge of SQL window functions? What’s the best way to practice them at home? Here are some suggestions. Learning something new feels great, but it’s also arguably the easiest part of gaining knowledge. You’ve probably experienced that yourself. You struggle with learning an idea, and then you finally get it! There’s the feeling you’ve learned something. And then, very soon, you practically have to start all over again with the very same concepts.
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The Best SQL Social Media Groups and Channels to Follow in 2020

by Jakub Romanowski
12 Jun 2020 We get news, advice, and funny videos from Facebook, Twitter, and YouTube. Why not use social media to help you learn SQL? You wake up and the first thing you do is check for Facebook notifications. Do you take a photo of your breakfast and share it with friends on Instagram? Maybe you argue with someone on Twitter about which James Bond was the best? Or maybe you are recording a short TikTok video of you singing Lady Gaga?
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What’s an SQL Inline Query?

by Kamil Bladoszewski
11 Jun 2020 Have you ever heard the term “inline query”? How are they different from subqueries and derived tables? Have you looked this up in numerous places and still don’t know the answer? Let’s embark on a journey and find out together! The first time I heard the term “inline query”, I was a little bit surprised. It doesn’t sound like one of SQL’s nuances and I thought I knew all the basic concepts.
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Monthly SQL Challenges

by Dorota Wdzięczna
10 Jun 2020 SQL learners sometimes need challenges. Do you want to test your problem-solving skills or your knowledge of SQL? Then take our monthly SQL Challenges! We prepare them on LearnSQL.com every month. Each Challenge relates to a different interesting topic and will help you keep your SQL game sharp. In this article, you'll discover what our LearnSQL.com Monthly Challenges are and where to find them. We’ll also look at the Challenges collected in our Monthly SQL Challenge Mini Track.
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Practical Examples of When to Use Non-Equi JOINs in SQL

by Kateryna Koidan
9 Jun 2020 If you think that two tables in SQL can be joined only using the common field, you will be excited to learn that there are other ways of joining. Non-equi JOINs use different kinds of comparison operators in the JOIN condition. In this article, I’ll guide you through non-equi JOIN examples to show the common use cases for this type of JOIN. Equi JOIN vs. Non-Equi JOIN How do you usually join two tables in SQL?
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