sql - 重新格式化结果的 SQL 查询

Question

这是示例“销售”数据表

这是所需的输出结果集

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下面是将从该 SQL 语句生成的不想要的结果集的示例。

SELECT Vendor, SUM(Markdown), SUM(Regular), SUM(Promotion), SUM(Returned)
FROM sales
GROUP BY Vendor, Date

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有没有办法只通过 SQL 获得所需的结果集？

我们在 IBM iSeries 上运行 SQL DB2 数据库。

我确实意识到这是尝试执行此操作的一种非常奇怪的方法……我们只是想找到一种方法来根据需要取回结果集，而无需通过代码对结果进行任何手动转换。

Answer 1

你需要使用UNION语句

尝试，

SELECT Vendor, 'Markdown' as Type,  SUM(Markdown) as Amount 
FROM sales 
GROUP BY Vendor, Date

UNION

SELECT Vendor, 'Regular' as Type, SUM(Regular) as Amount  
FROM sales 
GROUP BY Vendor, Date

UNION

SELECT Vendor, 'Promotion' as Type, SUM(Promotion) as Amount 
FROM sales 
GROUP BY Vendor, Date

UNION

SELECT Vendor, 'Returned' as Type, SUM(Returned) as Amount 
FROM sales 
GROUP BY Vendor, Date