Articles Cookbook
13 Jun 2024
Gustavo du Mortier

SQL CTEs: A Complete Overview of Common Table Expressions

This article provides a detailed guide to everything you need to know about common table expressions (CTEs), from the basic definition to the most complex recursive queries. If the database you use supports CTEs, here’s everything you need to get the most out of it. Common table expressions – also called CTEs, WITH clauses, or recursive queries (although this last name is actually a specific application) – are a relatively new feature of SQL.
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11 Jun 2024
Jill Thornhill

SQL LAG() Function

The LAG() function – one of SQL’s window functions – is an important tool for planning and trend analysis. In this article, I’ll demonstrate how to include SQL LAG() in your queries using a few real-world examples. SQL window functions, also known as analytical functions or OVER functions, add a new dimension to data analysis. They allow you to include aggregates or data from other rows alongside the current row.
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6 Jun 2024
Jakub Romanowski

Transitioning to a Database Career: A Guide for Beginners

Whether you're looking to become a database administrator or a data analyst or to explore other roles, I've got you covered! In this article, you’ll learn about the insights and strategies you need to launch your database career successfully. Considering a career in databases but not sure where to start? This guide is designed to help beginners navigate the world of database careers with ease. Understand the essential skills needed, learn to get hands-on experience, and explore the benefits of networking with professionals.
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4 Jun 2024
Maria Durkin

The SQL BETWEEN Operator

SQL comparison operators are essential tools for filtering data in database queries. Among these operators, the BETWEEN operator stands out as an important tool for specifying ranges inside datasets. SQL comparison operators, such as BETWEEN, are useful for filtering data in database queries. The BETWEEN operator allows you to select rows within a given range, making it ideal for tasks like segmenting an audience by age ranges, identifying thresholds for items between certain quantities, or categorizing performance based on exam scores.
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2 Jun 2024
Jakub Romanowski

Course of the Month: 2023 Advanced Monthly SQL Practice

Enhance your SQL skills this June 2024 with our exclusive offer on the 2023 Monthly SQL Practice Sets - Advanced course, available for free for a limited time! As summer rolls in, it's the perfect time to learn new skills or brush up on the ones you've got. This June, why not seize the chance to deepen your SQL expertise with some challenging exercises drawn straight from the business world?
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31 May 2024
LearnSQL.com Team

New Monthly SQL Practice for June 2024!

In our June 2024 SQL Practice, you will meet Christine, the manager of a gym downtown, who seeks help in gaining essential insights from the gym database. She wants to understand various aspects: the popularity of each trainer, the average price for a training session, members with active plans, and more. Can you use your SQL skills to lend her a hand? It should not be too challenging if you have completed our SQL Basics course or have a solid grasp of fundamental SQL concepts.
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30 May 2024
Jakub Romanowski

Best Books for Learning PostgreSQL

Explore the world of PostgreSQL with our handpicked selection of the best books available. Whether you’re new to database management or looking to sharpen your skills, these resources are perfect for mastering the comprehensive features of PostgreSQL. I've been diving deep into PostgreSQL lately, and I'm excited to share the five best PostgreSQL books that have really helped me along the way. Whether you're just starting out or you're looking to deepen your expertise, there's a book here for everyone.
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29 May 2024
Agnieszka Kozubek-Krycuń

Top 100+ SQL Interview Questions and Practice Exercises

Are you gearing up for a SQL interview? This article is packed with over 100 SQL interview questions and practical exercises, organized by topic, to help you prepare thoroughly and approach your interview with confidence. SQL is essential for many jobs, like data analysis, data science, software engineering, data engineering, testing, and many others. Preparing well for a SQL interview is crucial, no matter what role you're aiming for.
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28 May 2024
Jorge Sandoval

15 SQL Server Practice Exercises with Solutions

Enhance your SQL Server proficiency with our SQL Server practice exercises. Each of these 15 practical T-SQL tasks includes a detailed solution to help you improve your querying skills. You know how everyone says, "Practice makes perfect"? Well, it couldn't be truer for SQL. The real learning happens when you start working with queries, tables, and data. If you're looking to sharpen your skills in MS SQL Server, you're in the right spot.
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23 May 2024
Jakub Romanowski

Which Database Is Best for Small Projects?

If you're tackling a small project and need to pick the best database for managing and analyzing your data, this article will help. I'll compare PostgreSQL and MySQL, two top choices for data analysis, to make your decision easier. Read on! Are you just starting to explore the world of databases and feeling a bit uncertain about which one to choose for your small projects? I remember feeling the same way when I first started.
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