Articles Cookbook
11 Aug 2021
Tihomir Babic

How to Find the Nth-Highest Salary by Department with SQL

Learn how to find the nth-highest salary in SQL, and you’ll learn how to get the nth value in any data. In this article, I’ll focus on one problem and give you several solutions to that problem. The problem is stated in the title already: find the nth-highest salary by department using SQL. This may sound too specific. But by learning how to solve this, you’ll be able to find the nth value in any data, not just salaries.
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10 Aug 2021
Andrew Bone

What Is the UPDATE Statement in SQL?

The SQL UPDATE statement is used to update existing data in your database. This article will explain its syntax and show you clear examples of the UPDATE statement in action. Effectively updating existing data in a database is required for anyone using SQL; data is only useful if it is kept up-to-date and relevant. In this article, we’ll examine the syntax of the UPDATE statement in great detail. Then we’ll dive into detailed step-by-step examples that will drive home the rules, potential uses, and limitations associated with the SQL UPDATE statement.
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6 Aug 2021
Karolina Niewiarowska

I Needed a Good SQL Course… So I Chose SQL Basics.

Why did I decide to take a SQL course? And how did I come across LearnSQL.com? It’s story time! Did I ever think that my professional career would deal with databases? Absolutely not. It didn’t even cross my mind that it would happen. Let me explain why I started learning SQL … and how I got to where I am today. Meet the SQL Newbie I suppose few people have their lives planned from A to Z.
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5 Aug 2021
Ignacio L. Bisso

How to Define a Window Frame in SQL Window Functions

The window function is a super powerful resource of the SQL language. At the core of any window function, there is a set of records, called the window frame, defined using an OVER clause. Knowing what records are in the window frame, how they are ordered, and what their upper and lower bounds are, are critical in understanding how window functions work. In this article, we will analyze and explain with examples how you can define different types of window frames.
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4 Aug 2021
Andrew Bone

Use SQL on a Movie Database to Decide What to Watch

We’ll demonstrate how to use SQL to parse large datasets and gain valuable insights, in this case, to help you choose what movie to watch next using an IMDb dataset. In this article, we’ll be downloading a dataset directory from IMDb. Not sure what to watch tonight? Are you browsing Netflix endlessly? Decide what to watch using the power of SQL! We’ll be loading an existing movie IMDb dataset into SQL.
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3 Aug 2021
Jakub Romanowski

Course of the Month: Creating SQL Reports in SQL Server

This is another in our series of free SQL Courses of the Month. This time, you can learn SQL Reporting in MS SQL Server for free. Do you want to be able to prepare even better SQL reports? Or maybe you have some basic knowledge of SQL Server (one of the major SQL dialects) and would like to go a step further? This is the course for you.
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29 Jul 2021
Michal Stín

How to Use SQL to Calculate Customer Lifetime Value (LTV)

Working with data is an essential skill for marketers in today's data-driven world. As a marketer myself, I decided to create a series of articles about calculating key performance indicator (KPI) metrics for SaaS (Software as a Service) companies. We’ll start by calculating customer lifetime value (LTV) using SQL. Data is one of today’s most valuable resources. If you work in a SaaS company, you are flooded with a huge amount of data every day.
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28 Jul 2021
Zahin Rahman

An Overview of SQL Text Functions

In this article, we will discuss the ins and outs of the most common SQL text functions, which make it possible for you to find and work on string values. Before we dive into text functions, let’s quickly recap what an SQL function is. Simply put, a function is a predefined built-in piece of code that you can use in your SQL query. For example, the functions SUM(), AVG(), and COUNT() are applied to numerical variables to calculate the sum, average, and number of records respectively.
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27 Jul 2021
Jakub Romanowski

How to Improve New Employee Onboarding with SQL Courses

Are you looking for something to improve the onboarding process of new employees at your company? If they will be working with databases and SQL, and if you need resources for them to learn quickly, choose interactive SQL online courses. You’ve just hired some new employees. Great! After a long recruitment process, you have finally managed to find people who can do the job and meet your expectations. You may have even used our advice on why it makes sense to Practice SQL Before Interviewing a Potential Employee.
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23 Jul 2021
Dorota Wdzięczna

SQL SUM() Function Explained with 5 Practical Examples

Aggregate functions are an important part of SQL knowledge – and there’s no better place to start learning them than with the SUM() function. In this article, you can expand or refresh your SQL with 5 practical examples of SUM(). SQL allows us to do more than select values or expressions from tables. Most operations on relational databases use aggregate functions like SUM() to do computations on data.
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