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Self-Join and Window Patterns
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Self-Join and Window Patterns

HardSQL · PostgreSQL

Problem

Write a query utilizing a self-join and window functions to identify user engagement patterns across consecutive days on Roku.

Use daily_user_activity as the source table. Treat activity dates as consecutive when they differ by exactly one calendar day.

Output

  1. One row per user with a consecutive-day activity pair.
  2. Columns: user_id, first_activity_date, next_activity_date, first_day_sessions, next_day_sessions, and pair_number.
  3. Exclude users without a consecutive-day pair. Order by user_id, then first_activity_date.

Schema

daily_user_activity
ColumnTypeDescription
activity_idPKINTUnique activity record identifier
user_idINTRoku user identifier
activity_dateDATECalendar date of user activity
sessionsINTNumber of Roku sessions on the activity date
Tablesdaily_user_activity
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