Articles Cookbook
30 Sep 2021
Ignacio L. Bisso

What Is the OVER() Clause in SQL?

Window functions are one of SQL’s most powerful resources, but they are not frequently used by the average SQL developer. In this article, we will explain how you can define different kinds of window frames using the OVER clause. The OVER clause is essential to SQL window functions. Like aggregation functions, window functions perform calculations based on a set of records – e.g. finding the average salary across a group of employees.
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29 Sep 2021
Martyna Sławińska

Why Use Primary Keys and Foreign Keys in Databases?

Relational databases organize data in a standardized manner. All data is entered into tables, the so-called relations. The tables are linked with one another to create connections between the data. The backbone of any relational database is the primary and foreign keys. Read along to find out why they are so important. In this article, we focus on the reasons why relational databases use primary and foreign keys. First, we review what primary and foreign keys are.
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28 Sep 2021
Tihomir Babic

Difference Between ROWS and RANGE in Window Functions

Are you familiar with ROWS and RANGE window functions but not sure how they are different? This article makes those differences clear. In using SQL window functions, you’ve probably come across ROWS and RANGE clauses. If you haven’t, they are both parts of the Window Functions course. If you have, it’s quite likely you have been left confused why there are two keywords for the same function. Well, they are not the same!
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24 Sep 2021
Kateryna Koidan

7 Things Every Data Engineer Should Know

People generate massive amounts of data every day. To get insights from data, organizations need to capture and process them efficiently. That is when data engineers are called up. In this article, I’ll discuss the data engineering role and the skill set necessary to succeed in the role. As the world generates more and more data every year, the IT industry creates new roles to deal with it. These roles include data analysts, data scientists, machine learning engineers, and data engineers.
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23 Sep 2021
Himanshu Kathuria

Find Top Salaries by Department with SQL

This article shows how to get the total salary by department for an organization, using the GROUP BY functionality of SQL. We explain the SQL GROUP BY clause in detail along with conditional filtering using a HAVING clause. Understanding the salary outlay for an organization is one of the common starting points for business leaders. It helps them see who in the organization has the highest total salary cost, department-wise.
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22 Sep 2021
Tihomir Babic

The 7 Best Articles about the SQL Recursive Query

Do you want to learn about recursive queries but don’t know where to start? Here’s our selection of seven articles that should help you with diving into the recursive queries world. I won’t lie to you. Learning and understanding recursive queries can be difficult. But difficult things are usually worth trying. And by learning recursive queries, you’re making sure you know how to work with this very powerful tool.
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21 Sep 2021
Kateryna Koidan

5 Practical Examples of Using ROWS BETWEEN in SQL

SQL window functions are tremendously useful for calculating complex aggregations like moving averages or running totals. The ROWS clause allows you to specify rows for your calculations, enabling even more sophisticated window frames. Here are five practical examples of leveraging the ROWS BETWEEN clause in SQL. Window functions (also called OVER functions) compute their result based on a sliding window frame (i.e. a set of rows). They are similar to aggregate functions in that you can calculate the average, total, or minimum/maximum value across a group of rows.
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17 Sep 2021
Dorota Wdzięczna

How to Export a CSV File From a T-SQL Query

Knowing SQL queries to select data from databases allows you to obtain information easily. However, there are many situations in which we need to export data to another platform or application. The CSV file is a solution to this problem. If you'd like to master complete SQL, try out our interactive SQL from A to Z track. It contains 7 hands-on SQL courses that will take you from a beginner to an advanced SQL user.
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16 Sep 2021
Kateryna Koidan

How Developers Can Build SQL Skills

Even though you cannot build an application using SQL, employers continue to add SQL skills to their job requirements for software developers. In this article, I’ll elaborate on why developers need to know SQL and how you can learn SQL most efficiently. As a developer, you may work on different kinds of projects. Not all of your projects require doing string manipulation, but that doesn’t mean you don’t need to know how to do this.
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15 Sep 2021
Himanshu Kathuria

Top 10 Tools for Business Analytics

Business Analytics is one of today’s hottest career fields. However, success as a business analyst requires that you learn the right skills and software programs. Let’s see what tools you should know if you want to be a business analyst. With the world generating immense amounts of data – and having systems in place to capture and manipulate that data to fuel business growth – job opportunities for business analysts are only going to grow.
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