W3Schools: A first resource to learn SQL
It contains interactive tutorials and tests your knowledge along the way with quizzes
A data analyst recently asked me for a resource to learn SQL. I really like the free tutorials on W3Schools; they are easy to follow, and they have quizzes along the way to test your understanding. If you dedicate yourself, you can finish the SQL tutorials in one day.
In my career as a statistician, I often use SQL to extract a dataset from a database. Some of the relevant skills include
sorting a dataset by 1 or more variables (in ascending or descending order)
calculating summary statistics (such as the sum, average, minimum, maximum, the number of rows, and the number of unique values of a particular variable)
joining 2 or more datasets together
filtering a dataset based on a condition
aggregating a dataset by a categorical variable
SQL is essential for anyone who wants to work with data, whether you are in analytics, data analysis, statistics, biostatistics, data science, or machine learning. Learn it well!
If you are reading my posts for the first time: I'm Eric Cai, a statistician based in Toronto, Canada. I write about statistics, communication, and career development for professionals in data & analytics. Subscribe to get my articles delivered to your inbox at 9:30 AM Eastern time on Monday to Friday.