Question

我正在寻找一种在mysql中分组多个列的方法。表几乎是：

Customer, Product, Date

Joe, Apple, 2011-01-01
Henry, Banana, 2011-05-26
Sally, Peach, 2011-06-02
Jane, Strawberry, 2010-06-25

我想做的是计算每个客户购买的产品数量，并在一年中将其分组。

所以它看起来像。

COUNT（产品）|一月|二月|三月....... |总

如果我只使用GROUP BY产品，我可以使用MONTH（日期）

Banana, January, 2
Banana, February, 3
Banana, March, 1

等等。

有没有办法做到这一点，以便我获得尽可能多的行，因为我有不同的产品，然后是每个月的一列？我真的不想在PHP后面这样做，因为它变得非常慢。非常感谢，已经！

Answer 1

SELECT Product,
 SUM(CASE WHEN MONTH(date) =  1 THEN 1 ELSE 0 END) Jan,
 SUM(CASE WHEN MONTH(date) =  2 THEN 1 ELSE 0 END) Feb,
 SUM(CASE WHEN MONTH(date) =  3 THEN 1 ELSE 0 END) Mar,
 SUM(CASE WHEN MONTH(date) =  4 THEN 1 ELSE 0 END) Apr,
 SUM(CASE WHEN MONTH(date) =  5 THEN 1 ELSE 0 END) May,
 SUM(CASE WHEN MONTH(date) =  6 THEN 1 ELSE 0 END) Jun,
 SUM(CASE WHEN MONTH(date) =  7 THEN 1 ELSE 0 END) Jul,
 SUM(CASE WHEN MONTH(date) =  8 THEN 1 ELSE 0 END) Aug,
 SUM(CASE WHEN MONTH(date) =  9 THEN 1 ELSE 0 END) Sep,
 SUM(CASE WHEN MONTH(date) = 10 THEN 1 ELSE 0 END) Oct,
 SUM(CASE WHEN MONTH(date) = 11 THEN 1 ELSE 0 END) Nov,
 SUM(CASE WHEN MONTH(date) = 12 THEN 1 ELSE 0 END) Dec,
 COUNT(date) Total
FROM 
 MyTable
GROUP BY 
 product

我如何GROUP BY多行/列？

1 个答案: