Data Science Educational Resources
StrataScratch is a data science educational platform with over 1,000+ real interview questions from your favorite companies.
SQL
Mastering SQL DENSE_RANK(): A Comprehensive Guide
How do you use SQL DENSE_RANK() to rank data in SQL? This guide will help you become a master in SQL ranking window functions.
Nathan Rosidi -
Advanced SQL Interview Questions You Must Know How to Answer
Advanced SQL interview questions that every data scientist should know. It is quite important to understand what is being tested and how you can prepare for it.Nathan Rosidi -
Different Types of SQL JOINs that You Must Know
In this article, we will discuss different types of SQL JOINs and show practical examples to help you wrap your head around a variety of JOINs in SQL.
Irakli Tchigladze -
Facebook Data Engineer Interview Questions
Interview questions for all the data engineers that wish to work at Meta/Facebook. We carefully selected the interview questions to reflect the data engineer job description as closest as possible.Nathan Rosidi -
Computing Cumulative Sum in SQL Made Easy
Showing you what the cumulative sum is and how to calculate it in SQL. We’ll go through three distinct methods, so you can use whichever method you like best.Nathan Rosidi -
SQL COALESCE() Function: A Guide for PostgreSQL Users
Learn how to handle null values with ease and efficiency using the versatile COALESCE() function in PostgreSQL, with practical examples and insights.Nathan Rosidi -
SQL BETWEEN Operator: Selecting the Range of Values
Learn how to select the data interval using the SQL BETWEEN. We will show you its syntax and different scenarios of using it in filtering and labeling data.Nathan Rosidi -
Technical Skills Needed as a Data Analyst with 1-2 Years of Experience
An overview of the top must-have technical skills a data analyst needs to stay competitive in the job market.
Vivek Sankaran -
Uber SQL Interview Questions
Breaking down the solution to one of the interesting Uber SQL interview questionsIrakli Tchigladze -
Illustrated Guide About Self Join in SQL
Mastering SQL Self Joins: how they work, why they multiply rows, and when to use them for comparisons, retention, and deduplication.Nathan Rosidi -
What Is SQL GROUP BY and How to Use It?
The article discusses the seven most typical uses of SQL GROUP BY. We’ll go through its syntax and coding examples to give a taste of real-life SQL coding.Nathan Rosidi -
Learn to Use a Recursive CTE in SQL Query
Master recursive CTEs in SQL through eight real-world use cases with ready-to-use datasets, common mistakes, performance tips, and interview questions.
Tihomir Babic -