我有實體有2個答案y/n。SQL Server 2008,如何計算不同的值的變化
我需要計算在stage1和stage2之間將回答從'n'更改爲'y'的實體的數量。
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
我試過,但這個不工作(因爲它計算誰改變答案的所有實體)
select
entity, count(distinct answer)
from
myDB
where
stage between '1' and '2'
group by
entity, answer
,但我不明白爲什麼這不起作用,結果出來全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單獨的列或單列? – Rahul
你不能有兩個同名的列... – jarlh
抱歉,單列。我使它看起來像兩列... – Nayana