NULL Keys in Joins

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

Domain

SQL

Difficulty

easy

Seniority

junior

Problem

A downstream dashboard is reporting fewer content views than expected. The content_views table has 100 records, but some views were logged without a user association. Write a query that pairs content_views to users on user_id and returns each view's ID, user ID, and username. Then reason about why the result has fewer than 100 rows.

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