如何将常量值更改为 SQL 中的列 header？

Question

SQL查询：

select type,count(*), 'Active'                            
   from file where removed = '0'                                
union all 
select type,count(*), 'Removed' 
   from file where removed = '1'

给出：

 TYPE                     COUNT ( * )   Constant value  
  A                         24,168      Active       
  A                              1      Removed      
  B                          8,280      Active       
  B                          1,263      Removed

但是，我怎样才能将 SQL 更改为：

TYPE                     Active  Removed   
A                         24,168    1       
B                          8,280  1,263

补充可选问题：包含以下总数的最佳方法是什么？

TYPE                     Active  Removed   
A                         24,168      1       
B                          8,280  1,263  
Total                     32,448  1,264

这是我对补充的最佳回答，如果您发现任何不足或改进，请告诉我：

select 
    type, 
    sum(CASE WHEN removed = '0' THEN 1 ELSE 0 END) 'Active',
    sum(CASE WHEN removed = '1' THEN 1 ELSE 0 END) 'Removed'                            

from file                                
Group by type

union all

select 'Total',
sum(CASE WHEN removed = '0' THEN 1 ELSE 0 END) 'Active',
sum(CASE WHEN removed = '1' THEN 1 ELSE 0 END) 'Removed'                            

from file

感谢所有发表评论或回答的人，感谢您的帮助。

Answer 1

使用case表达式做条件聚合：

select type,
       count(case when removed = '0' then 1 end) as "Active",                            
       count(case when removed = '1' then 1 end) as "Removed"                           
from file                       
group by type

如果有很多行除 0/1 以外的其他删除值，并且该列已编入索引，则可以抛出一个

WHERE removed IN ('0','1')

加快速度！

Answer 2

你可以试试：

select 
    type, 
    sum(CASE WHEN removed = '0' THEN 1 ELSE 0 END) 'Active',
    sum(CASE WHEN removed = '1' THEN 1 ELSE 0 END) 'Removed'                            
from file                                
Group by type

Answer 3

为了在没有 union 的情况下得到答案的总数，请尝试：

select 
  coalesce(type, 'Totals') type,
  sum(CASE WHEN removed = '0' THEN 1 ELSE 0 END) Active,
  sum(CASE WHEN removed = '1' THEN 1 ELSE 0 END) Removed
from file                                
Group by rollup(type)

这适用于 v6.1 及更高版本。

如何将常量值更改为 SQL 中的列 header？

How do I change a constant value to a column header in SQL?

sql

db2

db2-400