SQL錯誤代碼：1242 /如何在表中轉換我的代碼？

Question

儘管我閱讀了很多文檔和網頁，但我仍然沒有如何讓代碼工作。

select 
(select count(*) from toto where (ddate between '2012-01-01' and '2012-12-31') group by produit) "2012", 
(select count(*) from toto where (ddate between '2011-01-01' and '2011-12-31') group by produit) '2011', 
(select count(*) from toto where (ddate between '2010-01-01' and '2010-12-31') group by produit) '2010' 

我有一個SQL錯誤代碼：1242消息。是的，這是正常的，因爲我確實有超過1行返回。

我該如何處理？隨着使用PIVOT？但是如何？

Answer 1

試試這個;

select produit, 
sum(case when ddate between '2012-01-01' and '2012-12-31' then 1 else 0 end) as '2012', 
sum(case when ddate between '2011-01-01' and '2011-12-31' then 1 else 0 end) as '2011', 
sum(case when ddate between '2010-01-01' and '2010-12-31' then 1 else 0 end) as '2010' 
from toto 
where ddate between '2010-01-01' and '2012-12-31' 
group by produit 

Answer 2

您可以使用下面的方法樞數據：

select produit, 
    COUNT(case when ddate = '2012' then produit end) as Year_2012, 
    COUNT(case when ddate = '2011' then produit end) as Year_2011, 
    COUNT(case when ddate = '2010' then produit end) as Year_2010 
from 
(
    select produit, 
     year(ddate) ddate 
    from toto 
    where ddate between '2010-01-01' and '2012-12-31' 
) src 
group by produit