计数中的where子句

Question

有没有办法在t-sql中为count指定where子句？

我想做的事（请注意这是一个好的编码）是：

SELECT COUNT([column] WHERE [column]>20) AS [a], 
       COUNT([column] WHERE [column]<20 AND [column]>10) AS [b] 
FROM [table];

而不是两次查询

SELECT COUNT(*) FROM [table] WHERE [column]>20;
SELECT COUNT(*) FROM [table] WHERE [column]<20 AND [column]>10;

Answer 1

使用简单的案例陈述：

select
count (case when [column]>20 then 1 else null end) as [a],
count (case when [column]<20 and [column]>10 then 1 else null end) as [b]
from
table