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Data Modeling and Queries
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Data Modeling and Queries

MediumSQL · PostgreSQL

Problem

Design a data model and write queries on it to answer questions.

Asked in the onsite stage. Create a model containing users, experiences, and activity sessions, then report engagement for January 2025.

Output

  1. One row per experience, including experiences with no January sessions.
  2. Columns: experience_name, creator_name, active_users, total_minutes, and avg_session_minutes.
  3. Include distinct active users and ignore sessions outside January 2025. Sort by active users descending, then experience name ascending.

Schema

users
ColumnTypeDescription
user_idPKINTUnique user identifier
display_nameVARCHAR(100)User display name
experiences
ColumnTypeDescription
experience_idPKINTUnique experience identifier
experience_nameVARCHAR(150)Experience name
creator_user_idINTUser who created the experience
sessions
ColumnTypeDescription
session_idPKINTUnique session identifier
experience_idINTExperience used during the session
user_idINTUser associated with the session
session_startTIMESTAMPSession start timestamp
duration_secondsINTSession duration in seconds
Tablesusersexperiencessessions
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