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SQL: Failed Transactions in Window
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SQL: Failed Transactions in Window

MediumSQL · PostgreSQL

Problem

Write a query to identify users who have had more than three failed transaction attempts within a five-minute window.

Use the users and transaction_attempts tables. Consider only attempts whose status is failed.

Output

  1. One row per qualifying user.
  2. Return user_id, email, max_failed_attempts_in_5_minutes, and first_detected_at.
  3. Sort by the maximum count descending, then user_id ascending.

Schema

users
ColumnTypeDescription
user_idPKINTUnique user identifier
emailVARCHAR(255)User email address
transaction_attempts
ColumnTypeDescription
attempt_idPKINTUnique transaction attempt identifier
user_idINTUser associated with the attempt
attempted_atTIMESTAMPTimestamp when the attempt occurred
statusVARCHAR(50)Outcome of the transaction attempt
Tablesuserstransaction_attempts
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