Account Activity Lifecycle

SQL practice question · Hard · Analytics · Facebook

account_history has one row per advertiser and active year (advertiser_id, activity_year); duplicates are possible. The current year is the latest activity_year in the table and the previous year is current - 1. Classify every advertiser: 'Existing' if active in both the current and previous year; 'Resurrected' if active in the current year, not in the previous year, but in some earlier year; 'New' if the current year is their only active year; 'Churned' if not active in the current year. Output columns: advertiser_id, status. Order by advertiser_id ascending.

Table: account_history

Schema of account_history
ColumnType
advertiser_idINTEGER
activity_yearINTEGER
Sample rows of account_history
advertiser_idactivity_year
12025
12026
22025
32026
42024
42026
Expected output on the sample data
advertiser_idstatus
1Existing
2Churned
3New
4Resurrected

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