Dataford
Interview QuestionsInterview GuidesExperiencesMock InterviewsPricing
Get started

Average Order Value Query

MediumSQL · PostgreSQL00:00
Practice interviewer
In session
5 left
00:00

Your question is Average Order Value Query. Start with the requirements and the two tables on the right.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

You need to log in / sign up to run or submit.

Problem

Insight Global's reporting team needs a customer-level view of spending activity. Write a PostgreSQL query that calculates the average order value for every customer during the rolling year ending on the current date. For the sample data, assume the current date is 2026-08-29.

Requirements

  1. Return every customer, including customers with no qualifying orders.
  2. Include orders from CURRENT_DATE - INTERVAL '1 year' through CURRENT_DATE, inclusive.
  3. Calculate the average of order_amount, ignoring NULL amounts, and round the result to two decimal places.
  4. Sort the output by customer_id in ascending order.

Schema

customers
ColumnTypeDescription
customer_idPKINTEGERUnique customer identifier
customer_nameVARCHAR(100)Customer display name
orders
ColumnTypeDescription
order_idPKINTEGERUnique order identifier
customer_idINTEGERReferences customers.customer_id
order_dateDATEDate the order was placed
order_amountNUMERIC(10,2)Order value
Tablescustomersorders
Your solutionPostgreSQL
You need to log in / sign up to run or submit.
Run a query to see results