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Deduping Clinical Transactions
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Deduping Clinical Transactions

MediumSQL · PostgreSQL

Problem

Write a query to find duplicate records in a clinical transactions table and explain your strategy for removing them.

Treat records as duplicates when all business columns match: patient, transaction date, provider, transaction type, amount, and source system. Keep the record with the lowest transaction_id and identify the remaining records for removal.

Output

  1. One row per duplicate record that should be removed
  2. Columns: transaction_id, patient_id, transaction_date, provider_id, transaction_type, amount, and duplicate_of_transaction_id
  3. Exclude the retained record, and order by transaction_id ascending

Schema

clinical_transactions
ColumnTypeDescription
transaction_idPKINTUnique transaction identifier
patient_idINTPatient identifier
transaction_dateDATEDate on which the transaction occurred
provider_idINTHealthcare provider identifier
transaction_typeVARCHAR(30)Clinical transaction classification
amountDECIMAL(10,2)Transaction amount, including adjustments
source_systemVARCHAR(30)System that supplied the transaction
Tablesclinical_transactions
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