SQL如何将数据分为单独的月份列

问题描述

因此，我正在运行此查询以获取客户的名称，订购的总金额以及他们提交的订单数量。通过此查询，我获得了他们从三月到七月的全部历史记录，我想要的是名称，三月总金额/订单数量，四月总金额/订单数量，可能总金额/订单数量.....等

SELECT customer_name,MONTH(created_on),SUM(amount),COUNT(order_id)
FROM customer_orders
WHERE created_on BETWEEN '2020-03-01' AND '2020-08-01' 
GROUP BY customer_name,MONTH(created_on)

解决方法

如果要将值放在单独的列中，请使用条件聚合：

SELECT customer_name,SUM(CASE WHEN MONTH(created_on) = 3 THEN amount END) as march_amount,SUM(CASE WHEN MONTH(created_on) = 3 THEN 1 ELSE 0 END) as march_count,SUM(CASE WHEN MONTH(created_on) = 4 THEN amount END) as april_amount,SUM(CASE WHEN MONTH(created_on) = 4 THEN 1 ELSE 0 END) as april_count,. . .
FROM customer_orders
WHERE created_on >= '2020-03-01' AND
      created_on < '2020-08-01' 
GROUP BY customer_name;

请注意，我更改了日期过滤器，因此它不包括2020-08-01。