Articles Cookbook
5 Mar 2021
Tihomir Babic

How to Get Descendants of a Parent in SQL

Want to learn how to handle family trees and find descendants of a parent? By reading this article, you’ll learn how to handle hierarchical data. Finding descendants from a parent is a common problem in SQL. If you imagine a family tree, the basic building block that forms the relationships within it is the parent-child relationship. The parent-child relationship is precisely what defines all hierarchical data. Another example of hierarchical data is the manager-employee relationship.
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4 Mar 2021
Andrew Bone

What Do the Operators LIKE and NOT LIKE Do?

The SQL LIKE and NOT LIKE operators are used to find matches between a string and a given pattern. They are part of standard SQL and work across all database types, making it essential knowledge for all SQL users. Gaining an understanding of these operators will allow you to write better queries and demonstrate to potential employers that you have the skills required to filter through expansive data sets.
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3 Mar 2021
Kateryna Koidan

How to JOIN Tables in SQL

Do you need to display data stored in different tables? Then it’s time to use SQL JOINs! This can be a challenging topic for beginners, so I’ve prepared this comprehensive step-by-step guide on joining tables in SQL. Often, the information that you want to display is stored in several tables. In such cases, you’ll need to join these tables by specifying which rows should be combined with other rows. That’s exactly what JOIN does.
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26 Feb 2021
Martyna Sławińska

MS SQL Server vs. PostgreSQL: Which to Choose?

Choosing the DBMS you will use for a new project is a very important and difficult decision. Two popular choices are MS SQL Server and PostgreSQL. To help you decide which would be best for you, I'll compare their features, list pros and cons, and give you some examples. Your selection of database management system (DBMS) depends on the type of business or project you're implementing. First, you need to know:
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25 Feb 2021
Timothy Edison

How Much SQL Practice Do You Need to Become a Pro?

Are you wondering how long it will take to learn and practice SQL before you can call yourself a pro? In this article, I will try to help you answer this question. Being a pro in SQL can mean many different things. Some people would say that being a professional is about mastery of advanced SQL, i.e. window functions or complex subqueries. For other people, being a professional means getting paid for your skills.
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24 Feb 2021
Jakub Romanowski

SQL Terms Beginners Should Know - Part 3

This is the third part of my list of essential SQL terms for beginners. In the first, you learned what tables, relational databases, and queries are. In the second part of the tutorial, I told you about aliases, SQL JOINs, primary keys, and subqueries. Now, it's time for more advanced database terms. But don't be afraid! I won’t crush you with scientific definitions. I will explain everything simply so that you can easily understand.
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23 Feb 2021
Kate Stolarek

How to Use SQL to Filter Your Client Email Database

Looking for ways to be on friendly terms with your email database? Here's my way of using SQL to evaluate a promotion. A client database plays an essential role in developing your sales and marketing strategies. Having a clear and well-structured database has several benefits. For example, you can increase your company's revenue by managing your current and new clients – they can be monitored and offered special promotions. Moreover, such an effort develops customer satisfaction and increases value for your current customers.
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19 Feb 2021
Karolina Niewiarowska

Learn SQL And Start Your Journey Towards Personal Growth

Are you at the start of your career, unsure of the skills employers value most? Or perhaps you’re experienced but feel it’s time to refresh your skillset. Learning SQL can open doors to new opportunities. Keep reading to discover why SQL is essential for both personal and professional growth. Regardless of your career stage, you cannot neglect your personal development. Whoever does not move forward falls behind. As you start learning new things, new opportunities will open up for you, both in your personal and professional life.
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18 Feb 2021
Kamila Ostrowska

How to Practice PostgreSQL Online

PostgreSQL is hot right now!If you want to join a community of people passionate about data, this open-source database system is something you need to try. Like everything we teach on LearnSQL.com, PostgreSQL requires practice. To profit from Postgres – as this dialect is sometimes called – you need to start with the basics. You can watch some tutorials on YouTube or read articles to get to know what a Database Management System (DBMS) is.
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16 Feb 2021
Marija Ilic

What Is GROUP BY in SQL?

GROUP BY is a great SQL feature that allows you to perform powerful calculations on grouped data. Do you want to learn how to get powerful insights from your data? Would you like to know what GROUP BY does and when you should use it? If your answer is yes, keep reading. In this article, you will learn exactly that. Why You Need GROUP BY In today's digitized world – no matter what business you are in – database tables are usually huge, with millions of records.
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