SQL Average Transaction Per Customer

EasySQL · PostgreSQL00:00

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Your question is SQL Average Transaction Per Customer. Start with the requirements and the one table on the right.

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Problem

xAI's finance analytics team wants a per-customer view of transaction values. Write a PostgreSQL query that calculates the average transaction amount for transactions recorded during the past year. Assume CURRENT_DATE is 2026-08-29 when evaluating the sample output.

Requirements

Include only transactions from the last year, including transactions on the boundary date.
Return one row per customer_id, with the average rounded to two decimal places, ordered by customer ID.
Ignore NULL transaction amounts as PostgreSQL's AVG function does by default.

Schema

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
customer_id	INT	Customer associated with the transaction
amount	NUMERIC(10,2)	Transaction amount
transaction_date	DATE	Date the transaction occurred

Tablestransactions

Your solutionPostgreSQL

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