Industry
Miscellaneous
Employer
Side Project
Timeline
1 month
8 Week SQL Challenge
Data Analysis, PostgreSQL, DataGrip
Completed SQL exercises across business cases to sharpen data analysis skills, covering customer segmentation, churn analysis, and financial reporting for e-commerce, subscriptions, and fintech.
Outcome
+140
SQL exercises
8
business cases
Why I Took This Challenge
I completed this challenge to enhance my data querying and analysis skills, becoming a more autonomous PM in data-driven decision making, eliminating dependency on analysts for exploratory queries and metric validation.
Skills Demonstrated
Through these progressively complex cases, I developed proficiency in the following SQL skills and techniques: - Advanced analysis: PERCENTILE_CONT(), moving averages - Aggregate Functions: SUM(), COUNT(), AVG(), MIN(), MAX() , GROUP BY - Conditional Statements: CASE WHEN ... THEN ... ELSE ... END - Window functions: RANK(), LAG(), LEAD(), PARTITION BY - Complex joins & CTEs for multi-table analysis - Date manipulation & time-series analysis - And others
Environment Setup
For these exercises, I chose PostgreSQL as it has been the most popular DBMS for the second consecutive year, according to the 2024 Stack Overflow Developer Survey. This reinforces my SQL skills while staying aligned with industry standards and current trends. Additionally, I used DataGrip as my database IDE and set up the provided databases on a local PostgreSQL server to simulate a more realistic environment, rather than using the sandbox DB Fiddle environment provided by the case author.
Sample Queries — Query 1: Customer churn analysis (Foodie-Fi case), Query 2: Funnel analysis with conditional aggregation (Clique Bait case), Query 3: Balance calculation with window functions (Data Bank case).
