Happy Thanksgiving! Using SQL to Prepare a Traditional Menu

Thanksgiving is a holiday many Americans celebrate with their families and friends, seated around a table loaded with a hearty feast. The most prominent of all dishes is, of course, the turkey. However, at least a few other specialties are also cooked for Thanksgiving. Do you find it hard to choose what to prepare? If so, we’ve got a solution for you: a special SQL query that will help you pick the best dishes. Gathering Our Thanksgiving Recipes Before we

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Descriptive Statistics: Calculating the Mean in Various Data Series

The mean (average) is one of the most valuable and most frequently used measures in descriptive statistics. Why is it so widely used, and why is it important to know how to calculate the arithmetic mean? Perhaps the most convincing argument is that the mean is used in virtually every area of life. With the arithmetic mean, you can calculate the average daily television viewing time for citizens of a given country, average volume of coffee drunk by a typical

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Spooky Scary NULL: Unexpected Danger Lurking in Your Database

Relational databases often store the value NULL in their tables. If you’re not familiar with NULL and what it is, you could run into unexpected problems. In this article, we’ll take a look at how the IN and EXISTS operators work with NULL. What Is NULL? In SQL, NULL is a special value indicating that a particular piece of data doesn’t exist in the database. For SQL beginners, it’s often a source of problems. Each column in a table requires

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Popular SQL Interview Questions for Business Analysts

SQL is an extremely desirable skill for anyone in today’s market—not just those in the IT sector. It’s becoming increasingly common for employers to require at least a basic knowledge of SQL in professions related to finance, statistics, banking, and business analytics. In this article, we will focus on the SQL questions one can expect during an interview for a business analyst (BA) position. What Is a Business Analyst? Simply put, a business analyst is someone who analyzes a variety

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Why Learn SQL?

Nowadays, data are gathered from a variety of sources, and information is of great value to organizations. However, with an increasing amount of data comes the need for databases that can store information for retrieval and analysis by trained specialists. Thus, proper data analysis is in high demand in our digital world. Relational databases, which logically group information into chunks, are basically used to store and organize large amounts of data. Of course, if you’re looking to retrieve any kind

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An Illustrated Guide to Multiple Join

So far, our articles in the “An Illustrated Guide” series have explained several join types: INNER JOINs, OUTER JOINs (LEFT JOIN, RIGHT JOIN, FULL JOIN), CROSS JOIN, self-join and non-equi join. In this final article of the series, we show you how to create SQL queries that match data from multiple tables using one or more join types. Join Types in SQL Queries Before we start discussing example SQL queries that use multiple join types, let’s do a short recap

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