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Monthly Ledger Reconciliation SQL
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Monthly Ledger Reconciliation SQL

MediumSQL · PostgreSQL

Problem

Write a SQL query to aggregate monthly transaction volumes and identify reconciliation anomalies across multiple ledger tables.

Use posted transactions and completed settlements. Treat a month as anomalous when transaction counts or monetary volumes differ.

Output

  1. One row per month present in either ledger.
  2. Columns: month_start, transaction_count, transaction_volume, settlement_count, settlement_volume, volume_difference, and reconciliation_status.
  3. Include unmatched months, sort by month_start ascending, and label each row MATCHED or ANOMALY.

Schema

transaction_ledger
ColumnTypeDescription
transaction_idPKINTUnique transaction identifier
transaction_dateDATEDate the transaction was recorded
amountNUMERIC(12,2)Transaction monetary amount
statusVARCHAR(20)Transaction processing status
settlement_ledger
ColumnTypeDescription
settlement_idPKINTUnique settlement record identifier
transaction_idINTRelated transaction identifier when available
settled_atDATEDate the settlement was recorded
settled_amountNUMERIC(12,2)Settlement monetary amount
statusVARCHAR(20)Settlement processing status
Tablestransaction_ledgersettlement_ledger
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