在 SQL 服务器中使用 SUM Function 时如何显示 Null 值

Question

我在 SQL 服务器中的脚本有问题，我需要显示 NULL 值的总共 3 列

这是我的查询：

SELECT 
    Bucket,
        (SELECT SUM (OutstandingPrincipal)  FROM example
        WHERE [status] = 'Covid')
    AS Covid,
        (SELECT SUM (OutstandingPrincipal) FROM example
        WHERE [status] LIKE '%Disbu%')
    AS Disburs_After,
        (SELECT SUM (OutstandingPrincipal) FROM example
        WHERE [status] = 'Non Covid')
    AS Non_Covid
FROM example
WHERE Bucket IS NOT NULL
GROUP BY 
    Bucket

这怎么可能？ 提前致谢

Answer 1

如果我正确理解您的数据，则不需要所有这些子查询，您可以使用conditional aggregation ：

select bucket,
       sum(case when status = 'Covid' then OutstandingPrincipal end) as covid,
       sum(case when status like '%Disbu%' then OutstandingPrincipal end) as Disburs_After,
       sum(case when status = 'Non Covid' then OutstandingPrincipal end) as Non_Covid
from example
where bucket is not null
group by bucket