SQL Hacks To Control Family Budget On Black Friday Weekend

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If you’re in the US, chances are you’ve been eagerly awaiting the approach of Black Friday just as much as Thanksgiving. Though the shopping frenzy takes hold of nearly everyone, some people have to stick to their budgets and shop prudently. In this article, we’ll take a look at how generating an SQL report can help you track how much your family spent shopping on Black Friday. Storing Black Friday Purchases in a Database Before we can create an SQL

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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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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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SQL Window Functions By Explanation

In our previous post, we explained how SQL window functions work by example. We started with some very simple, basic functions. Let’s extend it by explaining subclauses in window functions. SQL window functions are a great way to compute results from a set of rows rather than a single row. As you know from our first article, the “window” in window function refers to the set of rows. We showed you some examples of simple window functions like RANK and

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High Performance Statistical Queries: Linear Dependencies Between Continuous Variables

In my previous articles, I dealt with analyses of only a single variable. Now it is time to check whether two variables of interest are independent or somehow related. For example, a person’s height positively correlates with shoe size. Taller people have larger shoe sizes, and shorter people have smaller shoe sizes. You can find this and many more examples of positive associations at: http://examples.yourdictionary.com/positive-correlation-examples.html. A negative association is also possible. For example, an increase in the speed at which

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So You Want to Be a Data Scientist?

A career in data science is hot right now. What is a data scientist, and how can you become one? Very few of us said “I want to grow up to be a data scientist” when we were kids. But now, in the age of Big Data and economic uncertainty, a career in data science is looking mighty attractive. If you like the idea of working with information and earning a good paycheck, read on. If you’re interested in cutting-edge

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