将服装产品的行显示为列

Posted 2023-03-23

【中文标题】将服装产品的行显示为列

【英文标题】：display rows as columns for apparel products

【发布时间】：2014-10-23 01:55:12

【问题描述】：

我正在做电子商务网站。试图将服装尺寸保持为列

sn-p 没有“group by productid”子句

select d.id,
(case when s.sizeid = 1 then 1 else 0 end) as "S"  ,
(case when s.sizeid = 2 then 1 else 0 end) as "M",
(case when s.sizeid = 3 then 1 else 0 end) as "L"  ,
(case when s.sizeid = 4 then 1 else 0 end) as "XL",
(case when s.sizeid = 5 then 1 else 0 end) as "XXL"  
from datatest d
inner join stock s on d.id = s.productid

具有像这样的“按产品 ID 分组”结果

select d.id,
(case when s.sizeid = 1 then 1 else 0 end) as "S"  ,
(case when s.sizeid = 2 then 1 else 0 end) as "M",
(case when s.sizeid = 3 then 1 else 0 end) as "L"  ,
(case when s.sizeid = 4 then 1 else 0 end) as "XL",
(case when s.sizeid = 5 then 1 else 0 end) as "XXL"  
from datatest d
inner join stock s on d.id = s.productid
group by d.id

请帮帮我

【问题讨论】：

您需要什么帮助？期望的结果是什么？

【参考方案1】：

我猜你想要的是所有尺寸列的总和，共享相同的产品 ID。

SUM() 函数会在您使用 GROUP BY 时为您执行此操作

select d.id,
SUM( (case when s.sizeid = 1 then 1 else 0 end) ) as "S"  ,
SUM( (case when s.sizeid = 2 then 1 else 0 end) ) as "M",
SUM( (case when s.sizeid = 3 then 1 else 0 end) ) as "L"  ,
SUM( (case when s.sizeid = 4 then 1 else 0 end) ) as "XL",
SUM( (case when s.sizeid = 5 then 1 else 0 end) ) as "XXL"  
from datatest d
inner join stock s on d.id = s.productid
group by d.id