Articles Cookbook
30 Dec 2021
Tihomir Babic

How to Include Zero in a COUNT() Aggregate

Explaining how to include zero (0) counts in your SQL query result. Here’s the problem: you want to count something that doesn’t exist, and you want to show your result as zero. How do you do that in SQL? Using the COUNT() aggregate function is a reasonable first step. It will count all the data it finds and return the number of occurrences. But what if there are no occurrences of certain data?
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28 Dec 2021
Karolina Niewiarowska

Here’s How I Started Creating SQL Reports

Once upon a time, there was a girl who was just starting her adventure with learning SQL. As a marketer, one of her tasks was writing reports. Previously, she used Excel, a calculator, and written notes to prepare the reports her boss required. One day, it turned out that she could do her job much faster and easier. That was the day she read about SQL reports for the first time.
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23 Dec 2021
Ignacio L. Bisso

How to Use the SQL PARTITION BY With OVER

At the heart of every window function call is an OVER clause that defines how the windows of the records are built. Within the OVER clause, there may be an optional PARTITION BY subclause that defines the criteria for identifying which records to include in each window. Read on and take an important step in growing your SQL skills! What Is the PARTITION BY Clause in SQL? The SQL PARTITION BY expression is a subclause of the OVER clause, which is used in almost all invocations of window functions like AVG(), MAX(), and RANK().
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16 Dec 2021
Kamil Bladoszewski

Is SQL Case-Sensitive?

Is SQL case-sensitive? The question seems simple, and you may think it’s a yes-no question. However, the answer depends on multiple factors. Let’s take a look at the possible answers. First of all, this question can be understood in multiple ways. Which part of SQL are you asking about? Do you mean keywords (e.g., SELECT, WHERE, etc.), table and column names, or values in the columns? Which database management system (DBMS) do you have in mind?
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14 Dec 2021
Jakub Romanowski

Top 5 MS SQL Server Courses for Beginners

Every journey, including a career change, begins with the first step. If you're thinking about learning data analysis or strengthening your MS SQL Server skills arsenal, you've come to the right place. Here are the top 5 MS SQL Server online courses. Enjoy! You've probably heard that today’s organizations rely heavily on data analysis. You heard right. They are looking for employees who can navigate the world of databases and draw conclusions from data.
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9 Dec 2021
Tihomir Babic

How to Join Tables in SQL Without Using JOINs

Here’s how you can combine tables without the JOIN keyword. It seems like it shouldn’t be possible: join tables in SQL without using the JOIN keyword. But using the JOIN keyword is not the only way to join tables in SQL. This article will show you two additional methods for joining tables. Neither of them requires the JOIN keyword to work. They are: Using a comma between the table names in the FROM clause and specifying the joining condition in a WHERE Using UNION and UNION ALL.
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7 Dec 2021
Kateryna Koidan

Will SQL Ever Be Replaced?

Is it worth learning SQL? Is it possible that one of the modern programming languages or no-code solutions will replace SQL very soon? No; it is not that easy to replace SQL and relational databases. Let’s see why SQL is future proof – and why learning it will pay off for many years to come. If you are building your career in a data-driven company, you are probably looking into opportunities to enhance your skill set in data management and data analysis.
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26 Nov 2021
András Novoszáth

Here’s Why You Should Use SQL for Sales Analytics

Would you like to understand how your sales efforts play out so that you know where to put your focus? Do you want to empower your sales teams with sales analytics? This article shows you how you can use SQL to use your sales data to your advantage. If you work in sales, understanding the activities that produce results has financial consequences for you, your team, and your company. This is where sales analytics can really help you.
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25 Nov 2021
Kateryna Koidan

5 Best Practices for Writing SQL JOINs

These best practices for SQL JOINs will help you make readable SQL queries that deliver accurate, clear, and understandable output. Considering that relational databases are built around related tables, it’s no wonder that SQL JOINs – which allow you to combine information from multiple tables – are one of the primary skills acquired by SQL newbies. SQL JOINs course by LearnSQL.com is the perfect place to refresh your knowledge about JOINs.
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24 Nov 2021
Tihomir Babic

Top 5 SQL CTE Interview Questions

Here are five questions (and solutions!) on CTEs you’ll (probably) be asked at an interview. I’m not saying you will get these SQL CTE interview questions at every job interview. But when you do, they are probably along the lines of the five I’m about to show here. Other than theoretical questions about CTEs, there are not that many variations in the CTE scenarios evaluated by interviewers. Go through these five examples, and you get a good foundation for acing your interview!
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