SQL 如何根据现有列的计数为新列创建值？

我有一个正在读取的临时表，我想查看只有两个等级值的列之一 - 3 或 4，并构建两个新列 - 一个保存 3 的计数和另一个用于保存 4 的计数 - 按特定分组。我的代码看起来像这样。

Select Max(Counting) as Total
, student
, stdType
, Score3 = (SELECT count(*) from #tempBWMSHonors3 where score = '3')
, Score4 = (SELECT count(*) from #tempBWMSHonors3 where score = '4')
from #tempBWMSHonors3
group by student, stateID, grade, stdType

I also embedded an image that show an example of my temp table and what I'm trying to achieve (as well as the result I am getting - but don't want). []

我认为你只想要条件聚合，而不是子查询：

select Max(Counting) as Total, student, stdType,
       sum(case when score = '3' then 1 else 0 end) as Score3,
       sum(case when score = '4' then 1 else 0 end) as Score4
from #tempBWMSHonors3
group by student, stdType;

注意：如果分数是数字而不是字符串，则不应使用单引号作为常量。