想要一个SQL按值的范围在oracle中分组值

Question

我有一个表t1并且有一列名为days，所以我想将这些天分组1天到5天，6-15天和超过15天，然后计算每个组的计数，但是我不知道如何编写sql，谁能告诉我？结果应该看起来像下面：

Number Scope(days)  
    5  1-5 
    7  6-15 
    10  15+ 

Answer 1

如果我没有理解好，这可能是一个办法：

with t1(days) as ( 
    select 1 from dual union all 
    select 2 from dual union all 
    select 5 from dual union all 
    select 6 from dual union all 
    select 7 from dual union all 
    select 8 from dual union all 
    select 10 from dual union all 
    select 11 from dual union all 
    select 16 from dual union all 
    select 17 from dual union all 
    select 19 from dual union all 
    select 19 from dual 
) 
/* the query */ 
select count(*), 
     case 
     when days between 1 and 5 then '1-5' 
     when days between 6 and 15 then '6-15' 
     else '+15' 
     end  
from t1 
group by case 
     when days between 1 and 5 then '1-5' 
     when days between 6 and 15 then '6-15' 
     else '+15' 
     end 

给出：

COUNT(*) CASE 
---------- ---- 
     3 1-5 
     4 +15 
     5 6-15 

的想法是被什么东西聚集那就是说每个数字所在的“组”，并且您可以使用CASE轻松构建这样的信息。

Accordin到Jarlh的建议，这可以被改写为

select count(*), the_group 
from (
     select case 
       when days between 1 and 5 then '1-5' 
       when days between 6 and 15 then '6-15' 
       else '+15' 
       end the_group 
     from t1 
    )  
group by the_group 

显然，这假设你只有正数。