Cumulative Users by Signup Day

Problem

Return signup_date, new_users, and cumulative_users.

Why This Matters

SQL interviews usually test whether you can turn a business question into the right rows, grouping level, join type, and edge-case behavior.

Schema

users(user_id INTEGER, signup_date TEXT)

Examples

Constraints

• Return only the requested columns.
• Use deterministic ORDER BY when multiple rows are returned.
• Assume SQLite-compatible SQL unless the prompt states otherwise.