20 May 2025 Agnieszka Kozubek-Krycuń Beginner SQL Project: Build a Report With BigQuery and Looker Want to practice your SQL skills on a real dataset? In this beginner-friendly project, you’ll use BigQuery and Looker to explore Chicago’s crime data and build your first interactive report – no advanced experience needed! If you want to get better at SQL, nothing beats working on real projects. Practice is where your skills truly grow – and today, you’ll take a big step forward. In this beginner-friendly project, you’ll create a simple crime report based on the Chicago Crime public dataset, using BigQuery to write SQL queries and Looker Studio to build an interactive dashboard. Read more 13 May 2025 Agnieszka Kozubek-Krycuń SQL and Chill: 5 Fun Datasets to Practice With on a Friday Night Tired of boring practice datasets that make SQL feel like work? Kick back and sharpen your skills with five fun, quirky datasets that make learning SQL feel more like playing. It’s Friday night. You’re not in the mood to go out, there’s nothing good left to stream, and your brain is craving something a little more satisfying than scrolling your phone. So you fire up your laptop, open your SQL editor, and settle in for a different kind of unwind. Read more 6 May 2025 Agnieszka Kozubek-Krycuń SQL Intermediate Practice Questions Ready to take your SQL skills to the next level? These intermediate questions will help you practice real-world scenarios using GROUP BY, CASE WHEN, subqueries, CTEs, and more. If you’ve already mastered SQL basics and feel comfortable writing simple queries, it’s time to level up. Intermediate SQL skills are key to handling real-world reporting, deeper analysis, and solving more complex data tasks that go beyond basic SELECT statements. In this article, you’ll practice essential techniques like GROUP BY, CASE WHEN, subqueries, and Common Table Expressions (CTEs). Read more 29 Apr 2025 Agnieszka Kozubek-Krycuń How to Use Google BigQuery to Practice SQL for Free Want to practice SQL without installing anything or spending a dime? With Google BigQuery Sandbox, you can explore real datasets, write queries online, and build your SQL skills for free – no credit card required. This guide will show you how to get started step by step. What is Google BigQuery? Google BigQuery is a cloud-based data warehouse – a type of database made for storing and analyzing large amounts of data. Read more 17 Apr 2025 Agnieszka Kozubek-Krycuń Free Databases for Beginners: Where to Start? Not sure which database to start with? Here are the best free options for beginners along with why they’re great for learning SQL. If you're new to databases, one of the first questions you’ll probably ask is: Which database engine should I start with? With so many options available, it’s easy to feel overwhelmed. SQL databases power everything from small applications to massive enterprise systems, but not all of them are beginner-friendly. Read more 6 Mar 2025 Agnieszka Kozubek-Krycuń What are the Differences Between Database Engines? An Overview for Beginners If SQL is a standard language, why do databases like MySQL, SQL Server, Oracle, and PostgreSQL all exist? Do their differences matter? This article explains what sets them apart and why it’s useful to know – even if you’re not a database expert. My husband is a software tester. Occasionally, he uses SQL to pull data from a database – like checking if a user with access to three open projects sees the correct list, or modifying data for testing purposes. Read more 11 Feb 2025 Agnieszka Kozubek-Krycuń SQL GROUP BY The GROUP BY clause helps you summarize data by grouping rows with similar values. In this guide, we’ll show you how it works with simple examples. GROUP BY is an SQL clause that organizes data into groups based on one or more columns, so you can summarize data by calculating things like totals, averages, or counts for each group. To learn more about using GROUP BY in practice, try our interactive SQL Basics course with 129 hands-on practical exercises to help you master the basics of SQL, including GROUP BY . Read more 24 Oct 2024 Agnieszka Kozubek-Krycuń NULLs and Handling Missing Data in SQL Handling missing data (i.e. NULLs) in SQL can be challenging. NULLs can pose a lot of traps, especially if you don’t understand how they work. In this article, we’ll talk about dealing with NULL in SQL. We’ll also explain how to avoid common mistakes when working with NULLs. Having missing data in your database is an unavoidable reality of life. There are many reasons why you may have missing data in your database: the complete data isn’t yet available, users provide incomplete information, changes to the database schema, database malfunctions, human error, and more. Read more 29 May 2024 Agnieszka Kozubek-Krycuń Top 100+ SQL Interview Questions and Practice Exercises Are you gearing up for a SQL interview? This article is packed with over 100 SQL interview questions and practical exercises, organized by topic, to help you prepare thoroughly and approach your interview with confidence. SQL is essential for many jobs, like data analysis, data science, software engineering, data engineering, testing, and many others. Preparing well for a SQL interview is crucial, no matter what role you're aiming for. Read more 13 May 2024 Agnieszka Kozubek-Krycuń SQL FIRST_VALUE Function Discover the power of the FIRST_VALUE function, a window function that returns the first value in an ordered partition of the result set. This function is useful for anyone doing data analysis in SQL. Window functions are a powerful category of functions that enable doing sophisticated data analysis in SQL. These functions operate over a "window" of rows related to the current row, allowing for preparing complex reports like running totals, moving averages, preparing rankings, and others. Read more «« « 1 2 3 » »»