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Average Spend by User Cohort
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Average Spend by User Cohort

MediumSQL · PostgreSQL

Problem

Given two tables (users and transactions), write a query to find the average spend per user cohort for Pocket Fm.

Define a cohort by the month of users.signup_date. Include every registered user in the calculation, including users with no transactions, whose spend should be treated as zero. Ignore transactions that do not belong to a registered user.

Output

  1. One row per signup-month cohort.
  2. Columns: cohort_month, average_spend_per_user, and user_count.
  3. Sort by cohort_month ascending.

Schema

users
ColumnTypeDescription
user_idPKINTUnique Pocket Fm user identifier
signup_dateDATEDate on which the user registered
transactions
ColumnTypeDescription
transaction_idPKINTUnique transaction identifier
user_idINTUser associated with the transaction
amountNUMERIC(10,2)Recorded transaction amount
transaction_dateDATEDate on which the transaction occurred
Tablesuserstransactions
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