Two Wallets

A medium Data Modeling interview practice problem on DataDriven. Write and execute real data modeling code with instant grading.

Domain

Data Modeling

Difficulty

medium

Seniority

L5

Problem

We run an online education marketplace with two user types: students paying for access, and instructors paying for listing and promotion features. Both can subscribe to different plan tiers using multiple saved payment methods. Design the data model, then write the SQL for month-over-month subscription growth.

Summary

Two user types. Multiple payment methods. One messy billing table.

Practice This Problem

Solve this Data Modeling problem with real code execution. DataDriven runs your solution and grades it automatically.