我有实体有2个答案y/n。SQL Server 2008,如何计算不同的值的变化
我需要计算在stage1和stage2之间将回答从'n'更改为'y'的实体的数量。
entity || answer || stage
a || y || 1
a || n || 2
b || y || 1
b || y || 2
c || n || 1
c || n || 1
d || n || 1
d || y || 2
我试过,但这个不工作(因为它计算谁改变答案的所有实体)
select
entity, count(distinct answer)
from
myDB
where
stage between '1' and '2'
group by
entity, answer
,但我不明白为什么这不起作用,结果出来全0
select
entity,
case
when stage = '1' and answer = 'n' and
stage = '2' and answer = 'y' then 1
else 0
end as 'result'
from
myDB
where
stage between '1' and '2'
group by
entity, stage, answer
是那些TWP单独的列或单列? – Rahul
你不能有两个同名的列... – jarlh
抱歉,单列。我使它看起来像两列... – Nayana