用于生成所需输出的子查询选项

Question

这是我的疑问：

    select email_address, count(customer_id) AS order_count, sum((item_price - discount_amount) * (quantity)) AS order_total,
round(avg((item_price - discount_amount) * (quantity)),2) AS avg_order_total
from customers join orders 
using(customer_id)
join order_items 
using(order_id)
group by customer_id
having count(order_id) > 1 
order by round(avg((item_price - discount_amount) * (quantity)),2) desc

我的输出

想要输出

如何使用子查询生成所需的输出？不能使用限制BTW

Answer 1

以下是猜测，这是否有效，是否更好

SELECT
      c.customer_id
    , COUNT(o.customer_id) AS order_count
    , SUM((oi.item_price - oi.discount_amount) * (oi.quantity)) AS order_total
    , ROUND(AVG((oi.item_price - oi.discount_amount) * (oi.quantity)), 2) AS avg_order_total
FROM customers c
INNER JOIN orders o ON c.customer_id = o.customer_id
INNER JOIN order_items oi ON o.order_id = oi.order_id
GROUP BY
      c.customer_id
HAVING COUNT(o.order_id) > 1
ORDER BY
      ROUND(AVG((oi.item_price - oi.discount_amount) * (oi.quantity)), 2) DESC

我假设这些item_price，discount_amount，quantity来自order_items表，f不是真的更改＆＃34; oi。 ＆＃34;正确的别名。