Deduplicating logs (ROW_NUMBER)

Problem

Your event collector accidentally logged some clicks twice due to network retries. You need to keep only the earliest click event for each unique session. Write a query that outputs strategy with the value: "To deduplicate, partition by unique keys, calculate ROW_NUMBER() ordered by timestamp, and select only rows where the rank is 1."

Database Schema

This problem acts as a scratchpad. You will write your own DDL/DML or conceptual queries, so there is no predefined schema.

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Solution