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Repeat Purchase Window

A medium SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.

Domain
SQL
Difficulty
medium
Seniority
mid, senior

Problem

A churn model needs repeat-purchase signals. Find users who made another purchase within 1 to 7 days of a previous transaction, excluding same-day transactions. Return each qualifying user ID once.

Practice This Problem

Solve this SQL problem with real code execution. DataDriven runs your SQL queries against a live PostgreSQL database and grades it instantly.