mysql - 根据 SQL 中的不同元素，必需的 Sum 导致单独的列

Question

我是 SQL 的新手，基本上我需要根据不同的元素在单独的列中求和结果。

请在下图中找到我的表格和所需的结果。

请指导我如何使用 SQL 查询来获得所需的结果。

Answer 1

您可以使用条件聚合:

select payment,
       sum(case when product = 'A' then amount else 0 end) as a,
       sum(case when product = 'B' then amount else 0 end) as b,
       sum(case when product = 'C' then amount else 0 end) as c,
       sum(case when product = 'D' then amount else 0 end) as d,
       sum(amount) as total
from t
group by payment;