mysql sum and count per category append to matching category 行

Question

我正在尝试派生一个 MySQL 查询来转换这个:

product | sold
milk    |  6
milk    |  4
bread   |  3
bread   |  2
bread   |  2

对此；

product | sold | total order   | Total sold
milk    |  2   |       2       |     6
milk    |  4   |       2       |     6
bread   |  3   |       3       |     7
bread   |  2   |       3       |     7
bread   |  2   |       3       |     7

我已经能够毫无问题地查询总和和计数，但我似乎无法将其作为与产品匹配的新列加入。这可能吗？我试过 WITH ROLLUP 但它只是创建了另一行，而不是我想要的。

Answer 1

您可以将此表上的简单查询与以下聚合查询结合起来:

SELECT a.product, a.sold, b.total_order, b.total_sold
FROM   mytable a
JOIN   (SELECT   product, COUNT(*) AS total_order, SUM(sold) AS total_sold
        FROM     mytable
        GROUP BY product) b ON a.product = b.product