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 30 May 2023 Gustavo du Mortier How to Use SUM() with GROUP BY: A Guide with 8 Examples Explore some real-world examples of using SUM() and GROUP BY in SQL, from the most basic to the most sophisticated. SUM() is a SQL aggregate function that computes the sum of the given values. GROUP BY is a SQL clause that partitions rows into groups and computes a stated aggregate function for each group. Using these two functions together, you can compute total sums for a group of rows. In this article, we’ll see 8 different examples of how you can combine SUM() and GROUP BY to create many different reports. Read more 26 Jan 2023 Gustavo du Mortier How to Group by Multiple Columns in SQL When analyzing large data sets, you often create groupings and apply aggregate functions to find totals or averages. In these cases, using the GROUP BY clause with multiple columns unfolds its full potential. GROUP BY is a clause of the SELECT command. It allows you to compute various statistics for a group of rows. For example, you can use GROUP BY with an employee table to know how many employees are of each gender. Read more 17 Mar 2021 Gustavo du Mortier What Is a NULL in SQL? SQL uses NULLs as a special flag that signals the lack of a value for a field or a variable. NULLs should be used wisely so the database gives a faithful picture of the reality it represents. Some people associate NULLs with zeros; others think that NULL means “none”. In SQL, neither of these are true. Simply put, an SQL NULL means that we don’t have a value for that particular field. Read more