Question

我正在努力加强汇总（与年收入相比），汇总计算正确，但不是输入＆＃39; Grand Total＆＃39;在桌子的最后，＆＃39;袜子＆＃39;正在再次输入。

任何想法我做错了什么？

select coalesce(product_name, 'total') as product_name,  sum(price) as year_revenue
from orders 
    join product on orders.ProductID = product.ProductID
group by month(order_data) with rollup;

＆＃39; Blue Shirt＆＃39;，＆＃39; 69.93＆＃39;

＆＃39; Denim Jeans＆＃39;，＆＃39; 197.91＆＃39;

＆＃39; White Blazer＆＃39;，＆＃39; 94.97＆＃39;

＆＃39;袜子＆＃39;，＆＃39; 109.94＆＃39;

＆＃39;紧身牛仔裤＆＃39;，＆＃39; 73.96＆＃39;

＆＃39;迷你短裙＆＃39;，＆＃39; 31.98＆＃39;

＆＃39; White Blazer＆＃39;，＆＃39; 74.97＆＃39;

＆＃39; Black Blazer＆＃39;，＆＃39; 40.99＆＃39;

＆＃39; Shorts＆＃39;，＆＃39; 19.98＆＃39;

＆＃39; Mini Skirt＆＃39;，＆＃39; 85.96＆＃39;

＆＃39; Flare Blouse＆＃39;，＆＃39; 33.98＆＃39;

＆＃39;袜子＆＃39;，＆＃39; 7.98＆＃39;

＆＃39;袜子＆＃39;，＆＃39; 842.55＆＃39;

Answer 1

原因是您按MONTH(order_data)分组，而不是product_name。发生WITH ROLLUP时，按列分组的值会被NULL替换。如果您要将查询更改为：

SELECT MONTH(order_data) AS month, product_name, SUM(price) AS year_revenue
FROM orders
JOIN product ON orders.ProductID = product.ProductID
GROUP BY month WITH ROLLUP

您会在NULL列中看到month值。

要实现您的目标，请尝试将您的查询更改为：

SELECT IF(month IS NULL, 'Total', product_name) AS product_name, year_revenue
FROM (SELECT MONTH(order_data) as month, product_name, SUM(price) AS year_revenue
    FROM orders
    JOIN product ON orders.ProductID = product.ProductID
    GROUP BY month WITH ROLLUP)

合并卷起无法正常工作（MySql）

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