23 Feb 2023 Tihomir Babic Top 27 Advanced SQL Interview Questions with Answers Where can an SQL professional find a comprehensive guide to advanced SQL interview questions? The shortest answer is: here! We selected the 27 most important SQL questions and answered them for you. Preparing for an SQL interview is not easy, especially if your job requires the knowledge of advanced SQL. This article contains the 27 most commonly asked advanced SQL interview questions and provides detailed answers and resources for further reading. Read more 21 Feb 2023 Tihomir Babic 6 Useful Examples of CTEs in SQL Server How can you use CTEs in SQL Server in your everyday professional life as a data pro? We’ll answer this question by giving you six examples. CTE is short for Common Table Expression. This is a relatively new feature in SQL Server that was made available with SQL Server 2005. A CTE is a temporary named result. This result is available only for the query that runs it. It isn’t stored, so it doesn't take up disk space. Read more 19 Jan 2023 Tihomir Babic What Is a CTE in SQL Server? What is a CTE, and how do you write a CTE in SQL Server? Join us on a journey where we’ll see all the typical usage of a CTE in SQL Server. CTEs (or Common Table Expressions) are an SQL feature used for defining a temporary named result. You can think of it as a temporary table whose output is available only when the main query is run. This is practical because the CTEs result isn’t stored anywhere but can always be referenced inside the query like any other table. Read more 12 Jan 2023 Tihomir Babic How to Practice SQL Window Functions Online Learn and practice SQL window functions from the comfort of your home! Here’s how to do it. The last few years have shown that working from home has many benefits over the daily commute. No wonder people are reluctant to go back to the office! They have much more time while doing the same work. What do you do with the extra time? Whatever you want. It’s your time! Read more 13 Dec 2022 Tihomir Babic 5 Practical Examples of SQL’s WITH Clause These five practical use cases will make you want to use the SQL WITH clause daily. The WITH clause can help you write readable SQL queries and break complex calculations into logical steps. It was added to SQL to simplify complicated long queries. In this article, we’ll show you 5 practical examples of the WITH clause and explain how using it makes SQL queries more readable. The WITH clause is also called a Common Table Expression (CTE). Read more 10 Nov 2022 Tihomir Babic How to Use GROUP BY in SQL In this article, we’ll give you a step-by-step guide on using GROUP BY in SQL. Uncover the nuances of the GROUP BY clause and learn different ways of using it. GROUP BY is one of the most-used clauses in SQL. It moves you from simply selecting data from the database to grouping rows with the same column values into one group. When used with SQL’s aggregate functions, you can use GROUP BY to compute metrics like counting the number of instances or finding the total, average, minimum, or maximum value. Read more 8 Nov 2022 Tihomir Babic How to Use the PARTITION BY Clause in SQL We’ll be dealing with the window functions today. Specifically, we’ll focus on the PARTITION BY clause and explain what it does. PARTITION BY is one of the clauses used in window functions. In SQL, window functions are used for organizing data into groups and calculating statistics for them. It sounds awfully familiar, doesn’t it? Even though they sound similar, window functions and GROUP BY are not the same; window functions are more like GROUP BY on steroids. Read more 25 Oct 2022 Tihomir Babic An Overview of SQL Text Functions in PostgreSQL If you’re a PostgreSQL user and into data analysis, you’ve heard of the text functions or maybe even used them. But what are PostgreSQL’s most popular text functions? In today’s article, we’ll show you what they are and how to use them. As anyone who works with them knows, databases don’t contain only numerical values. Among other data types, databases also store text or string data. To use PostgreSQL effectively, you’ll have to know at least some of Postgres’ text functions. Read more 10 Oct 2022 Tihomir Babic SQL Courses for Software Testers In this article, you will learn why software testers need SQL and which courses are ideal for them to learn it. Do software testers need SQL? Oh yes, they do! They don’t necessarily use it all the time or take advantage of all its possible features. But a tool for accessing data in a database is essential for a software tester. And SQL is exactly that: a programming language designed specifically for handling data in relational databases. Read more 13 Sep 2022 Tihomir Babic Top 10 MySQL Interview Questions And Answers You learned SQL and now you want to use this valuable skill to get a better job. Now it’s time to prepare for the job interview. We’ve got ten MySQL interview questions and answers to help you with that. In today's hyperconnected world, knowing how to deal with it has become a necessary skill. That’s why you probably learned (or want to learn) SQL: either your job requires it or you realized that you need SQL to get a better job. Read more «« « 1 2 3 … 8 » »»