在特定条件下计算组内的百分比

Question

我有一张包含以下信息的客户订单表：

transaction_id	order_id	merchant_id	merchant_name	on_sale
423hk42b	tuy24u24g	20022	This LTD	Yes
h64v64h6	tuy24u24g	20022	This LTD	Yes
h3v45gh3	4i32ghi2i	22012	That SAS	No
b3k45b44	2b34u3bbu	12032	Stuff LTD	No
jb435bj4	1j3bh1hj3	12032	Stuff LTD	Yes
jb3k53kb	12hb3jbb1	13121	More Stuff LTD	Yes

我需要一个查询来查找每个商家的销售订单百分比。输出应如下所示：

merchant_id	merchant_name	total_orders	total_orders_on_sale	perc_sales_orders
20022	This LTD	1381	132	9.55
22012	That SAS	1313	87	6.62
12032	Stuff LTD	1323	34	2.56

对此有什么帮助吗？我尝试了窗口函数或 WITH 语句，但最终得到了错误的数字。

Answer 1

我想你想要聚合：

select merchant_id, merchant_name,
       count(*) as num_orders,
       sum(case when on_sale = 'Yes' then 1 else 0 end) as num_on_sale,
       avg(case when on_sale = 'Yes' then 1.0 else 0 end) as ratio_on_sale
from t
group by merchant_id, merchant_name;

编辑：

修改版可以使用count(distinct):

select merchant_id, merchant_name,
       count(distinct order_id) as num_orders,
       count(distinct case when on_sale = 'Yes' then order_id end) as num_on_sale,
       ( count(distinct case when on_sale = 'Yes' then order_id end) * 100.0 /
         count(distinct order_id)
       ) as ratio_on_sale
from t
group by merchant_id, merchant_name;