Средний чек — выручка / количество заказов за период.
$$AOV = \frac{Revenue}{Orders}$$
Средний чек — сумма выручки делённая на количество заказов. Базовый показатель e-commerce и доставки.
SELECT
date_trunc('day', created_at) AS day,
count(*) AS orders,
sum(amount) AS revenue,
avg(amount) AS aov,
percentile_cont(0.5) WITHIN GROUP (ORDER BY amount) AS median_aov
FROM orders
WHERE created_at >= now() - interval '30 days'
GROUP BY 1
ORDER BY 1;