Articles Cookbook
10 Feb 2022
Tihomir Babic

How to Query a Parent-Child Tree in SQL

What are parent-child tree structures in SQL? In this article, we answer that question, talk about query hierarchy, and demonstrate the five most common SQL queries you’ll need for these data structures. Yes, you can use SQL on a parent-child tree structure. I’ll show you how in this article. Along the way, I’ll walk you through five query examples, starting with the easiest and ending with the most complex.
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8 Feb 2022
Himanshu Kathuria

What Is the Future of the Data Engineer?

If you are wondering about the future of data engineering as a career and whether it is worth becoming a data engineer, then this article is for you. Here, I cover how lucrative the prospects are for data engineering and how you can get started and thrive in the domain. “Data” is probably one of the most used terms in our everyday business language today. A data engineer plays a pivotal role in developing the infrastructure required for data-related actions.
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3 Feb 2022
Karolina Niewiarowska

Is Learning PostgreSQL in 2022 Worthwhile?

You want to take a SQL course, but selecting the right one can be too challenging. Perhaps you don't know which dialect you should start with? PostgreSQL is one of the best options. Check out if it is worth it to learn PostgreSQL in 2022. When you search the web, there are many job advertisements for database specialists. Perhaps that is why you have chosen the direction toward development. Or maybe you are just fed up with Excel in your day-to-day duties (which is not surprising) and want to make work easier.
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27 Jan 2022
Kateryna Koidan

How Do You Get Rid of Duplicates in an SQL JOIN?

Do you have unwanted duplicates from your SQL JOIN query? In this article, I’ll discuss the possible reasons for getting duplicates after joining tables in SQL and show how to fix a query depending on the reason behind the duplicates. Data analysts with little experience in SQL JOINs often encounter unwanted duplicates in the result set. It’s challenging for beginners to identify the reason behind these duplicates in JOINs.
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25 Jan 2022
Tihomir Babic

The SQL OVER() Clause Explained

Here is a detailed explanation of the OVER() clause in SQL window functions. This is a detailed guide on using the OVER() clause in SQL window functions. I will focus specifically on this clause, which requires that you have at least a general idea of how window functions work. To make the best out of this article, take a look at the SQL Window Functions Cheat Sheet. Feel free to have it by your side as we go.
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20 Jan 2022
Andrew Bone

10 PostgreSQL Interview Questions and Answers

Job interviews are always stressful. Interviewing and getting asked technical questions about PostgreSQL is even more of a challenge! In this article, we’ll cover some of the PostgreSQL interview questions you can expect when applying for a new job. By the end of the article, you should be able to handle most of the questions you are likely to face. We’ve previously covered common questions you can expect at a SQL job interview, but this article will be focused on Postgres specifically.
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19 Jan 2022
Ignacio L. Bisso

What Is a Common Table Expression (CTE) in SQL?

The common table expression (CTE) is a powerful construct in SQL that helps simplify a query. CTEs work as virtual tables (with records and columns), created during the execution of a query, used by the query, and eliminated after query execution. A CTE is defined using a CTE query definition, which specifies the structure and content of the CTE. CTEs often act as a bridge to transform the data in source tables to the format expected by the query.
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18 Jan 2022
Kamila Ostrowska

The Top 5 SQL Courses and Learning Platforms for 2025

It’s the New Year! Time to start thinking what good you can do yourself in 2025. If you haven’t decided yet, we want to recommend learning something new – specifically, learning SQL. Thinking about learning SQL this year? If so, don’t waste time—SQL can open new career opportunities and even transform your future! To get the most out of your learning, it’s crucial to choose courses that match your goals.
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13 Jan 2022
Karolina Niewiarowska

Top 10 Beginner Online SQL Courses in 2022

Ready for New Year’s changes? Good, because now you have a perfect chance to achieve something new: Improve your skills by learning SQL! In this article, we’ll point you toward some great online SQL courses to help you meet this goal. SQL, or Structured Query Language, is the language used to communicate with relational databases. When you know SQL, you can add, delete, change, and make calculations using the data in a database.
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11 Jan 2022
Himanshu Kathuria

The Most Popular Databases for 2022

With the number of database products increasing with each passing year, it is important to understand which database best fits your use case. This article lists the top-ranking databases available in the market today. When something that first became popular in the early 1980s is not slowly fading away but is still evolving and becoming more relevant, you know it had to be an important invention. The database is no exception.
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