带有Count的SQL Server Pivot子句

我正在使用Microsoft SQL Server并尝试编写以下查询。我想用枢轴条款来计算美国和俄罗斯在2000年奥运会上的金牌数。但我对这两个国家的产出都是零。我知道我可以使用group by获得所需的结果（请参见下面的打印屏幕）。但是如何使用pivot子句实现这一点呢

请参见以下数据集和输出的打印屏幕

select 
    'Gold' as total_m, 
    ['USA'] as USA, ['RUS'] as RUS
from 
    (select 
         country, medal, year
     from 
         summer
     where 
         medal = 'Gold'
         and year = 2000 
         and country in ('USA', 'RUS')) as SourceTable
pivot
    (count(medal)   
     for country in (['USA'],['RUS'])) as PivotTable;

数据集

输出

分组依据

---

从

pivot

列列表中删除

引号

select 'Gold' as total_m, [USA] as USA, [RUS] as RUS
from 
    (select country, medal, year
     from summer
     where medal = 'Gold'
       and year = 2000 
       and country in ('USA', 'RUS')) as SourceTable
pivot
    (count(medal)   
     for country in ([USA],[RUS])) as PivotTable;

---

我发现用条件聚合来表达这一点更简单。这是一种可移植的语法，适用于大多数数据库，与特定于供应商的

pivot

语法相比，它不太复杂：

select mdel, 
    sum(case when country = 'USA' then 1 else 0 end) as USA,
    sum(case when country = 'RUS' then 1 else 0 end) as RUS
from summer
where medal = 'Gold' and year = 2000 and country in ('USA', 'RUS')
group by medal