Articles Cookbook
7 Mar 2023
Jill Thornhill

The Best YouTube Channels for Learning SQL

Discovering the best YouTube channel from which to learn SQL is essential for beginners and enthusiasts alike, as SQL learning doesn't have to be challenging. If you're wondering whether watching online videos is the most effective way to master SQL, it's crucial to explore and identify high-quality YouTube channels dedicated to teaching SQL. This approach ensures you gain a comprehensive understanding of SQL through engaging and informative content. So you’re thinking of learning SQL?
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28 Feb 2023
Ignacio L. Bisso

25 Advanced SQL Query Examples

One of the best ways to learn advanced SQL is by studying example queries. In this article, we'll show 25 examples of advanced SQL queries from medium to high complexity. You can use them to refresh your knowledge of advanced SQL or to review before a SQL interview. Table Employee Many of the examples in this article will be based on the following employee table. Only a few examples will be based on other tables; in these cases, the tables will be explained along with the example.
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23 Feb 2023
Tihomir Babic

Top 27 Advanced SQL Interview Questions with Answers

Where can an SQL professional find a comprehensive guide to advanced SQL interview questions? The shortest answer is: here! We selected the 27 most important SQL questions and answered them for you.  Preparing for an SQL interview is not easy, especially if your job requires the knowledge of advanced SQL. This article contains the 27 most commonly asked advanced SQL interview questions and provides detailed answers and resources for further reading.
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21 Feb 2023
Tihomir Babic

6 Useful Examples of CTEs in SQL Server

How can you use CTEs in SQL Server in your everyday professional life as a data pro? We’ll answer this question by giving you six examples. CTE is short for Common Table Expression. This is a relatively new feature in SQL Server that was made available with SQL Server 2005. A CTE is a temporary named result. This result is available only for the query that runs it. It isn’t stored, so it doesn't take up disk space.
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16 Feb 2023
Alexandre Bruffa

How to Concatenate Two Columns in SQL – A Detailed Guide

In SQL, concatenation is the operation of joining together strings, or pieces of text information. Learn how to concatenate two columns in SQL with this detailed guide. SQL concatenation is the process of combining two or more character strings, columns, or expressions into a single string. For example, the concatenation of 'Kate', ' ', and 'Smith' gives us 'Kate Smith'. Enhance your SQL skills with our interactive SQL Practice Set! This comprehensive course contains nearly 90 hands-on exercises, divided into five topic-based sections, including a section dedicated to SQL concatenation.
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14 Feb 2023
Nicole Darnley

Data Cleaning in SQL

Data cleaning is an important part of any data analysis. Here we’ll discuss techniques you can use to do data cleaning in SQL. I find it nearly impossible to focus on work when my desk is a mess. If it’s cluttered with paper, coffee mugs, or random toys my daughter has somehow snuck into my office, there is no chance I will be able to get anything done until my desk is back in order.
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9 Feb 2023
Nicole Darnley

Learn SQL for Data Analysis with LearnSQL.com

Discover how to learn SQL for data analysis and start making sense of your data today. Our guide provides a clear and simple SQL learning path for data analysts, helping you query databases and analyze data with ease. Whether you're starting from scratch or looking to polish your skills, we'll help you every step of the way. When I was in high school, I planned to go to college and major in interior design.
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7 Feb 2023
Jill Thornhill

Top SQL Certificates in 2023

SQL is an essential skill in today’s data-driven world. Looking for the best SQL certificates to further your career can be confusing. This article gives some pointers that will help you make the best choice to fit your goals. Who needs an SQL certificate? If you can write advanced SQL queries, surely you can just demonstrate your skills at the interview and you'll be hired. Yes ... but ... you won't reach the interview unless the recruiter invites you.
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2 Feb 2023
Valentyn Kucherenko

Introducing Our New Ultimate SQL Cheat Sheet!

Do you ever find yourself writing an SQL query and forgetting the syntax of some function? That sometimes happens to me too. Fortunately, LearnSQL.com has prepared this awesome Ultimate SQL Cheat Sheet you can always have on hand. Print it or save it to your browser's favorites and make your data querying more efficient! If you are looking for an SQL Cheat Sheet, it is safe to assume that you already know what SQL is.
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26 Jan 2023
Gustavo du Mortier

How to Group by Multiple Columns in SQL

When analyzing large data sets, you often create groupings and apply aggregate functions to find totals or averages. In these cases, using the GROUP BY clause with multiple columns unfolds its full potential. GROUP BY is a clause of the SELECT command. It allows you to compute various statistics for a group of rows. For example, you can use GROUP BY with an employee table to know how many employees are of each gender.
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