sql - 在sql中将空值和空值分组为一个

Question

我有一个查询，它提供了应用于数据库中事物的不同类别的细分：

select categories, count(*) from products 
group by categories

数据是这样的：

NULL                56
                    42
FooCategory         12
BlahCategory        2

我想分组NULL和<blank>

NoCategory          98
FooCategory         12
BlahCategory        2

Answer 1

尝试

select ISNULL(categories,'') as Categories, count(*) from products 
group by ISNULL(categories,'')

更新

有关所需参数，请参见此处

ISNULL（检查表达式，替换值）

Answer 2

尝试

select categories, 
case when categories is null or categories = ' ' 
then 'noCategory' else categories end as grouped,
count(*) 
from products 
group by grouped