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Validating Inconsistent Data
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Validating Inconsistent Data

MediumSQL · PostgreSQL

Problem

How would you approach validating a large, inconsistent dataset to ensure accuracy?

Use source_transactions as the dataset being validated and valid_accounts as the reference data. Write a query that returns every invalid source record and identifies the applicable data quality issues.

Output

  1. One row per invalid source record, ordered by source_id ascending
  2. Columns: source_id, account_code, validation_status, issue_count, account_check, duplicate_record
  3. Exclude records that have no detected validation issue

Schema

source_transactions
ColumnTypeDescription
source_idPKINTUnique identifier for the source record
account_codeVARCHAR(20)Account identifier supplied by the source dataset
transaction_dateDATEDate associated with the transaction
amountNUMERIC(12,2)Transaction amount
statusVARCHAR(20)Source transaction status
valid_accounts
ColumnTypeDescription
account_codePKVARCHAR(20)Reference account identifier
account_nameVARCHAR(100)Reference account name
is_activeBOOLEANWhether the account is currently active
Tablessource_transactionsvalid_accounts
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