的Oracle SQL计数在单一列的不同值的情况下(Oracle sql to count inst

我有一个状态列的表。 我想一个Oracle SQL查询，这将列出我只有一个行数在每个状态行。 对于例如，如果我的表

Table A
Id       Status  Fkey
1         20      500
2         20      500  
3         30      501
4         40      501
5         30      502

输出应该是

Fkey     Count_status20     Count_status30    Count_status40
500        2                      0                 0
501        0                      1                 1

这里的一个轻微的扭曲

Table B 
FKey TKey 
500   1001 
501   1001
502   1002 

现在，输出应为

TKey Count_status20     Count_status30    Count_status40 
1001     2                     1                    1 
1002     0                     1                    0

Answer 1:

如果您使用的是Oracle 11g，那么你可以使用PIVOT功能：

select *
from
(
  select tkey, status, 
    status as col
  from tableB b
  left join tableA a
    on a.fkey = b.fkey
) src
pivot
(
  count(status)
  for col in ('20' as Count_Status20, 
              '30' as Count_Status30,
              '40' as Count_Status40)
) piv;

请参阅SQL拨弄演示

如果你不使用Oracle11g的，那么你可以使用一个聚合函数CASE语句：

select tkey, 
  count(case when status = 20 then 1 else null end) as Count_Status20,
  count(case when status = 30 then 1 else null end) as Count_Status30,
  count(case when status = 40 then 1 else null end) as Count_Status40
from tableB b
left join tableA a
  on b.fkey = a.fkey
group by tkey

请参阅SQL拨弄演示

Answer 2:

select fkey,
       sum(case when status = 20 then 1 else 0 end) as count_status20,
       sum(case when status = 30 then 1 else 0 end) as count_status30,
       sum(case when status = 40 then 1 else 0 end) as count_status40,
from your_table
group by fkey

文章来源: Oracle sql to count instances of different values in single column