Articles Cookbook
8 Jan 2021
Martyna Sławińska

What Is Auto-Increment in SQL?

In this article, we’ll learn the basics of the auto-increment feature of SQL: what it is and how to use it efficiently. One of the many features offered by SQL is auto-increment. It allows us to automatically generate values in a numeric column upon row insertion. You could think of it as an automatically supplied default value – the next number in a number sequence – that’s generated when the row is inserted.
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5 Jan 2021
LearnSQL.com Team

Course of the Month: Standard SQL Functions

Are you dreaming of becoming a data analyst? Or maybe you just want to work effectively with your company’s databases? You can – with SQL functions. We’ve selected Standard SQL Functions to be our January 2021 SQL Course of the Month. What will you find inside? I asked Agnieszka Kozubek-Krycuń, Vertabelo's Chief Content Officer, about it. Here's what she said. What are SQL functions? The term reminds me of SELECT or JOIN.
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1 Jan 2021
Tihomir Babic

SQL JOIN Tips for Beginners

If you’re a beginner and want to know how to start using SQL JOINs in your queries, you’ve come to the right place. Using the SQL JOIN clause is necessary if you want to query multiple tables. Sooner or later, you’ll have to use more than one table in a query. It’s the nature of relational databases in general – they consist of data that’s usually saved in multiple tables; in turn, these form a database.
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31 Dec 2020
LearnSQL.com Team

Why Learn SQL This New Year?

In answering this question, we’ll take a look at the idea behind New Year’s resolutions, explore what SQL is, and see why learning it should be your goal for 2021. We’ve all heard of New Year’s resolutions, and we all have personal experience of how difficult it can be to see them through to a successful conclusion. We’ll examine the history of New Year’s resolutions, why they often fail, and how to ensure your resolution for learning SQL in 2021 doesn’t meet with the same fate as so many others that never made it past the end of January.
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25 Dec 2020
Ignacio L. Bisso

What Is a Database Index?

Database indexes are critical to query speed and efficiency. Learn when, why, and how to use them – and when not to – in this post. Indexes are very important database objects; they optimize data access and improve database performance by helping the database execute SQL queries faster. Why not take this opportunity to learn how indexes work and how to create them? What Is a Database Index? Indexes are data structures that can increase a database’s efficiency in accessing tables.
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23 Dec 2020
Dorota Wdzięczna

What Is an SQL INNER JOIN?

How do you combine data from different tables in one query? An SQL feature called JOIN is the most common operator used to create complex queries. Learn the basics in this article. SQL allows us to select data from more than one table. In fact, the whole idea of using relational databases is selecting data from related tables. And we can use SQL’s JOIN operator to do this. There are many types of JOINs in SQL.
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18 Dec 2020
Marija Ilic

SQL Window Functions for Managers: Who Gets a Raise?

Window functions are one of the most powerful features in modern SQL. In this article, you will learn why window functions are so great. I will list you the most useful window functions and briefly explain when and how you can use them. Simple SELECT statements, in combination with WHERE, GROUP BY, and HAVING, are sufficient for many analyses at work. I used standard SQL for many years before I realized there is something more.
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17 Dec 2020
Jakub Romanowski

The Best SQL Lectures on YouTube

YouTube contains a vast amount of information. The trick is to know how to find what’s valuable. If you type “SQL lectures” in the YouTube search engine, you will probably get a list of boring or unhelpful clips. However, there are hidden gems, and I’ve compiled a list of the best SQL talks I’ve found on YouTube so far. First, let's establish one thing. I didn't choose any YouTube SQL tutorials when making this list.
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16 Dec 2020
Zahin Rahman

Best Online Courses for SQL Window Functions

In this article, I will summarize the top online tutorials and courses available on SQL window functions for enthusiasts of data analysis, data science, and data engineering. The information is here to help you embrace the topic with ease and feel comfortable using window functions in SQL databases. SQL window functions can help you solve some of the most common analysis challenges in business: What are the N most popular products for each month of the year?
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15 Dec 2020
Tihomir Babic

How to Use CASE WHEN With SUM() in SQL

This article will teach you what a CASE WHEN expression is in SQL and how to use it with a SUM() function and a GROUP BY statement. The examples are included to bolster your understanding. The best way to learn about CASE WHEN and how to use it with SUM() is our hands-on course Creating Basic SQL Reports. It contains over 90 interactive exercises that will teach you different techniques how to create complex reports in SQL.
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