SQL多計數，GROUP BY個月

Question

我有表：

STATUS DEFECT DATE 

CLOSED IP  01.01.2012 
CLOSED TV  03.03.2012 
CLOSED ADSL  05.05.2012 
CLOSED ADSL  11.01.2012 
CLOSED TV  15.01.2012 
NEW  TV   
NEW  TV 

我想這組通過計數每個特定缺陷個月。這被認爲是狀態是封閉式

生成的表，我想是：

MONTH  TV ADSL IP 
January 1 1  1 
March  1 0  0 
May  0 1  0 

我使用的DB2數據庫，以便顯示個月，其作品的部分是：

select case month(timestamp_iso(DATE)) 
     when 1 then 'January' 
     when 2 then 'February' 
     when 3 then 'March' 
     when 4 then 'April' 
     when 5 then 'May' 
     when 6 then 'Jun' 
     when 7 then 'July' 
     when 8 then 'August' 
     when 9 then 'September' 
     when 10 then 'October' 
     when 11 then 'November' 
     when 12 then 'December' 
    end as Month 

from TABLE 
where STATUS='CLOSED' 
group by month(timestamp_iso(DATE)) 
order by month(timestamp_iso(DATE)) 

所以，我只是需要添加此部分進行計數。感謝

Answer 1

您可以使用另一個案例聲明來計數缺陷類別，這將限制計數爲一個類別中的缺陷：

select case month(timestamp_iso(DATE)) 
     when 1 then 'January' 
     when 2 then 'February' 
     when 3 then 'March' 
     when 4 then 'April' 
     when 5 then 'May' 
     when 6 then 'Jun' 
     when 7 then 'July' 
     when 8 then 'August' 
     when 9 then 'September' 
     when 10 then 'October' 
     when 11 then 'November' 
     when 12 then 'December' 
    end as Month, 
    count (case when defect = 'TV' then 1 end) TV, 
    count (case when defect = 'ADSL' then 1 end) ADSL, 
    count (case when defect = 'IP' then 1 end) IP 
from TABLE 
where STATUS='CLOSED' 
group by month(timestamp_iso(DATE)) 
order by month(timestamp_iso(DATE))