这是我在工作中尝试做的事情的混淆版本。假设我已经为我店里的顾客提供了这个月的数据 - 他们花了多少钱分成食物类型:
CUSTOMER FOOD_TYPE FOOD_TYPE_VALUE
1 SWEET 52.6
1 SAVOURY 31.0
1 DAIRY 45.8
1 DRINKS 12.1
2 SWEET 15.1
2 SAVOURY 44.1
2 DRINKS 23.4
3 SWEET 95.7
3 SAVOURY 20.0
3 DAIRY 10.8
3 DRINKS 57.1
我们决定客户3是我们理想的客户,因为他符合人口统计资料,我们希望逐月跟踪每个人的购物偏好分布与他的不同。
我可以通过以下方式获得每位顾客的每种食物类型的百分比分配:
SELECT
c1.customer,
c1.food_type,
100 * c1.food_type_value / sum(c2.food_type_value)
FROM
mytable c1 INNER JOIN mytable c2
ON c1.customer = c2.customer
group by c1.customer, c1.food_type, c1.food_type_value
但我在构建一个查询时遇到问题,这个查询会为我的理想客户提供一个具有匹配百分比值的列。即:
CUSTOMER FOOD_TYPE FOOD_TYPE_PERC IDEAL_PERC
1 SWEET 37 52
1 SAVOURY 22 11
1 DAIRY 32 6
1 DRINKS 9 31
关于如何在没有太多混乱的情况下实现这一目标的任何提示?
答案 0 :(得分:2)
将其加入包含理想客户的客户表的子集中:
SELECT
c1.customer,
c1.food_type,
100 * c1.food_type_value / sum(c2.food_type_value),
c3.FOOD_TYPE_VALUE / sum(c2.food_type_value) as IDEAL_PERC
FROM
mytable c1 INNER JOIN mytable c2
ON c1.customer = c2.customer
INNER JOIN (
SELECT FOOD_TYPE, FOOD_TYPE_VALUE
FROM mytable
WHERE customer = 3) c3
ON c2.FOOD_TYPE = c3.FOOD_TYPE
group by c1.customer, c1.food_type, c1.food_type_value, c3.FOOD_TYPE_VALUE
您对我的回答的评论建议您需要除以理想客户的FOOD_TYPE_VALUE,所以这样做:
SELECT
c1.customer,
c1.food_type,
100 * c1.food_type_value / sum(c2.food_type_value),
c3.IDEAL_PERC
FROM
mytable c1 INNER JOIN mytable c2
ON c1.customer = c2.customer
INNER JOIN (
SELECT s1.FOOD_TYPE,
100 * s1.FOOD_TYPE_VALUE / sum(s2.FOOD_TYPE_VALUE) IDEAL_PERC
FROM mytable s1
INNER JOIN mytable s2
on s1.customer = s2.customer
WHERE s1.customer = 3
GROUP BY s1.FOOD_TYPE, s1.FOOD_TYPE_VALUE) c3
ON c2.FOOD_TYPE = c3.FOOD_TYPE
group by c1.customer, c1.food_type, c1.food_type_value, c3.IDEAL_PERC