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SQL Window Functions Approach
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SQL Window Functions Approach

MediumSQL · PostgreSQL

Problem

Explain your approach to solving a problem using SQL window functions.

Illustrate the approach using the supplied transactions table. Return posted transactions with their rank by amount within each account, handling tied amounts and null amounts explicitly.

Output

  1. One row per posted transaction.
  2. Columns: transaction_id, account_id, transaction_date, amount, and amount_rank.
  3. Rank highest amounts first within each account; tied amounts share a rank and null amounts appear last.
  4. Order by account_id, amount_rank, then transaction_id.

Schema

transactions
ColumnTypeDescription
transaction_idPKINTUnique transaction identifier
account_idVARCHAR(20)Account associated with the transaction
transaction_dateDATEDate of the transaction
amountDECIMAL(10,2)Transaction amount
statusVARCHAR(20)Processing status of the transaction
Tablestransactions
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