Data Science Educational Resources
StrataScratch is a data science educational platform with over 1,000+ real interview questions from your favorite companies.
SQL
How to Use SELECT INTO in SQL for Analytics
SELECT INTO is an often-overlooked tool for analytics. Here we explain its syntax, use cases, how to use it in staging, and how it is tested in interviews.
Tihomir Babic -
Retention in SQL: How to Calculate User and Cohort Retention?
One-stop shop for product data scientists and job candidates: what is retention and its different types, how to calculate them, with the SQL application.
Shivani Arun -
What Is the Role of SQL Substring in Queries?
We explore the use of the SQL SUBSTRING() function to demonstrate its power in analyzing string formats, both for interview preparation and handling data.Shivani Arun -
Understanding FLOOR and CEILING Functions in SQL
We explore fundamental concepts of FLOOR and CEILING functions in SQL and demonstrate their value for interview preparation and handling data at scale.Shivani Arun -
How to Create Pivots in SQL (with examples)
Reshaping data using Pivots is table-stakes in data science. Learn about its importance, techniques, and implementation.Shivani Arun -
A Comprehensive Step-by-Step Guide to Full Outer Join in SQL
The FULL OUTER JOIN is a very useful but often overlooked SQL join. In this article, we’ll discuss how it works, when to use it, and give practical examples.
Nathan Rosidi -
How to Find the Minimum Value in SQL (with Examples)
Finding the minimum in SQL is easy: just use the MIN() aggregate function. In this article, you will learn how to do it in different real-case scenarios.Nathan Rosidi -
Mastering Row Number Handling in SQL Queries
ROW_NUMBER() is one of the essential ranking window functions in SQL. Learn where you can use it and how it works with ORDER BY and PARTITION BY window clauses.Nathan Rosidi -
Finding Maximum Values in SQL: Aggregation Techniques
MAX() in SQL is a straightforward aggregation method for finding maximum values. Learn here about its syntax and use cases through real interview examples.Nathan Rosidi -
CONCAT() in SQL: Tips and Techniques for Efficient Queries
CONCAT() in SQL is a data concatenation method. Learn about the tips, techniques, and practical examples of how to use it efficiently in SQL queries.Nathan Rosidi -
PySpark SQL Functions: Boost Big Data Processing with SQL
Leverage PySpark SQL Functions to efficiently process large datasets and accelerate your data analysis with scalable, SQL-powered solutions.Nathan Rosidi -
Counting Distinct Values in SQL: Tips and Examples
Using SQL COUNT(DISTINCT) is an easy way to count distinct values in SQL. However, it has its own quirks, which we’ll explain (with examples) in this article.Nathan Rosidi -