基于列的 SQL 内的 SUM 值

SUM Values within SQL based on a column

我有一个 table 如下所示:

我想转换数据,使最终产品看起来像这样:

这在 Excel 中很容易完成,但我希望能够通过 SQL 完成此操作,以便我可以自动生成报告。

我已经尝试了以下无效的代码:

SELECT 
SKU,
SUM(totals,ordered = 'Web') as Web_orders,
SUM(totals,ordered = 'App') as App_orders

FROM A

GROUP BY SKU

这将起作用:

SELECT 
SKU,
SUM(totals) filter (where ordered='web') as Web_orders,
SUM(totals) filter (where ordered='app') as App_orders
FROM A

GROUP BY SKU
ORDER by SKU;

如果您想要大写字母,您需要用“”将列名括起来。

您可以使用 case 表达式:

SELECT
  sku,
  SUM(case when ordered = 'web' then totals else 0 end) as "web",
  SUM(case when ordered = 'app' then totals else 0 end) as "app"
FROM A
GROUP BY sku