Tutorials

How to check and replace NULL values with SQL ISNULL()

How to check and replace NULL values with SQL ISNULL()

SQL ISNULL() is a practical function for checking the value of an expression. If a value is NULL, the function replaces it with a substitute value that you define in advance. In our dedicated article, we explain how this works using practical examples and reveal some of the…

Read more
How to use SQL EXISTS to check subqueries for certain values

How to use SQL EXISTS to check subqueries for certain values

The SQL EXISTS operator allows you to check whether a subquery contains a specific value. You can incorporate this subquery into a higher-level query and use it as a condition for execution. In this dedicated article, you will learn the structure of SQL EXISTS and find out how to…

Read more
What are SQL aliases?ChinnapongShutterstock

What are SQL aliases?

For table or column names that are long or difficult to read, it can help to create a temporary alternative name that’s simpler. SQL aliases do just this, providing simplified column and table names for queries. These aliases are only applied while the query is being carried out…

Read more
How to delete databases permanently with SQL DATABASE

How to delete databases permanently with SQL DATABASE

If you no longer need a database, you should permanently remove it using the SQL DROP DATABASE command. This dedicated guide explains how to use this command to get rid of single or multiple databases, explains what you should keep in mind when doing so, and lists the associated…

Read more
How to use SQL LIKE

How to use SQL LIKE

It’s easy to lose track of things in large datasets. The SQL LIKE operator is an essential tool for searching databases and making efficient queries. In this tutorial, we explain what the SQL LIKE operator is, what it’s used for and how to use SQL wildcards. We also show you…

Read more
How to use SQL UPDATERanjit Karmakarshutterstock

How to use SQL UPDATE

Do you need to update or change a table in SQL? The SQL UPDATE command allows you to update entries in a table as a whole or carry out changes on selected entries. In this article, we tell you everything you need to know about UPDATE, including its syntax, what it’s useful for…

Read more
How to configure Apache to use custom error pagesellisiaShutterstock

How to configure Apache to use custom error pages

By using custom error pages in Apache, you can ensure a smooth and appealing user experience, even when issues arise. We guide you through the process of configuring the Apache web server to display personalised error pages. From crafting the HTML files to adjusting the…

Read more
How to create a Mastodon serverRawpixel.comshutterstock

How to create a Mastodon server

Mastodon is a decentralised social network using open-source software. Similar to Twitter, it allows users or organisations to run their own servers (instances). You can scale your Mastodon server as your community grows while maintaining control over your data. We explain…

Read more
How to install and configure a dedicated FS25 server

How to install and configure a dedicated FS25 server

Want to play Farming Simulator 25 on a server that’s exclusively accessible to you and your friends and tailored to your preferences? In that case, a dedicated FS25 server on rented hardware is the perfect solution. But what hardware requirements need to be met? And how exactly…

Read more
How to add SQL comments to your codeESB Professionalshutterstock

How to add SQL comments to your code

SQL comments are essential for making code more readable and for temporarily disabling certain parts of the code. In this dedicated article, we’ll explore the different types of SQL comments, how to use them, and also provide you with some practical examples to illustrate their…

Read more
Page top