The Duplicate Detection Sprint

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

Domain

SQL

Difficulty

easy

Seniority

junior, mid

Problem

Ahead of a CRM migration, the data quality team needs to flag duplicate email addresses. For each email that appears more than once in the user records, show the email, how many times it appears, and the earliest and most recent signup dates.

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.