14 Nov 2024 Gustavo du Mortier INNER JOIN vs. OUTER JOIN: What’s the Difference? Deciding when to use INNER JOIN vs. OUTER JOIN is often challenging for beginners. In this article, you will find explanations and examples that will help you better understand the difference between these two joins. In SQL, JOINs allow you to combine data from different tables; INNER JOIN and OUTER JOIN are simply types of JOIN statements. Understanding their differences is critical if you work with relational databases. It is also crucial if you’re going for an SQL job interview: the difference between INNER JOIN and OUTER JOIN is among the most frequently asked SQL interview questions. Read more 22 Oct 2024 Gustavo du Mortier How SQL Helps Optimize Healthcare Workflows SQL is a universal language for healthcare data management and workflow optimization. In this article, we will see how to use SQL for everything from scheduling medical appointments to monitoring vital signs. Healthcare professionals must adhere to various processes to perform their duties. These processes, or workflows, are adapted to various situations – patient reception, diagnosis, monitoring, billing, clinical documentation, etc. While these workflows vary by type of care, setting (hospital, clinic, telemedicine), and the role of the practitioner, they all require the efficient and accurate handling of large volumes of critical information. Read more 1 Oct 2024 Gustavo du Mortier CTE vs. Temporary Table: What’s the Difference? SQL offers you two options to handle complex queries efficiently: CTEs and temporary tables. Read on to weigh the pros and cons of CTEs vs. temp tables. In SQL (Structured Query Language), a common table expression (CTE) lets you define a subquery and assign a name to it so that it can be used within a main query. A temporary table is a database table that you create explicitly, like any other table – but with the particularity that it disappears when you close the database connection in which it was created. Read more 24 Sep 2024 Gustavo du Mortier Rolling Total in SQL: What It Is and How to Compute It Calculating a rolling total in SQL is simple when you use window functions. These handy metrics are similar to running totals and moving averages, and they’ll help you build a clear picture of your data. In this article, we'll explain and explore rolling totals. In SQL, a rolling total is an important metric that helps you see how trends change over time, giving a clear picture of your data. It calculates a sum over a " Read more 10 Sep 2024 Gustavo du Mortier The MySQL CTE and How to Use It Common table expressions (CTEs) in MySQL give even more versatility to this popular database management system. Find out how to use CTEs to simplify complex queries and implement recursion. All programming languages have ways of simplifying problems by breaking them down into parts that can be solved individually. Users can unify the partial results to obtain a single final result. Thanks to something called common table expressions (CTEs), MySQL is now exception. Read more 13 Jun 2024 Gustavo du Mortier SQL CTEs: A Complete Overview of Common Table Expressions This article provides a detailed guide to everything you need to know about common table expressions (CTEs), from the basic definition to the most complex recursive queries. If the database you use supports CTEs, here’s everything you need to get the most out of it. Common table expressions – also called CTEs, WITH clauses, or recursive queries (although this last name is actually a specific application) – are a relatively new feature of SQL. Read more 14 May 2024 Gustavo du Mortier 11 SQL Common Table Expression Exercises In this article, we offer you 11 practice exercises that put your knowledge of common table expressions (CTEs) into practice. Each CTE exercise is accompanied by a solution and a detailed explanation. As the saying goes, “A little progress each day adds up to big results”. And that is undoubtedly true for SQL proficiency. Just as you should regularly go to the gym to keep your muscles toned, you should do common table expressions exercises often to keep your querying skills toned for heavy data analysis work. Read more 25 Apr 2024 Gustavo du Mortier 19 PostgreSQL Practice Exercises with Detailed Solutions You’ve probably heard the saying “practice makes perfect”. Find out if this phrase is true by trying the comprehensive set of PostgreSQL practice exercises that you will find in this article! To master any language, it is essential to practice it regularly so as not to lose the skill. This is as true for verbal communication as it is for programming. And SQL programming is no exception. Even the most seasoned PostgreSQL programmer needs to do PostgreSQL practice daily to perfect (and maintain) their skills. Read more 26 Mar 2024 Gustavo du Mortier How to Become a Big Data Engineer What is a Big Data engineer, and how is their skill set different from a data engineer? In this article, we explore the tools and platforms you’ll need to master as a Big Data engineer. To move from being a regular data engineer to a Big Data engineer, you need to acquire several new skills and learn to use several new tools. The good news is that Big Data still lets you use your good old SQL skills to manipulate and get information from data repositories. Read more 20 Feb 2024 Gustavo du Mortier MySQL Date Functions: Complete Analyst’s Guide Master MySQL date functions and acquire a powerful tool to work with date and time information in your data analyses. Working with date and time data is an essential part of data analysis. Here are just three examples: Analyzing historical time series data is crucial for discovering trends and making reliable forecasts based on chronological information. Stock market analysis examines time series data extensively, especially when automated trading algorithms are employed. Read more «« « 1 2 » »»