如何在使用group by的單個查詢中獲得多個計數記錄以及其他記錄

Question

我想從某個ftable中選擇某個文件名，日期，學位名稱的總數，完成和重命名數據如果存在計算上的用戶名條件的用戶名，如果用戶名不存在算作其餘爲已完成

---------------------------------------- 
file_nm | degree_nm| date_nm | user_nm 
---------------------------------------- 
X  | D_x  |02/05/2013| USER3 
X  | D_x  |02/05/2014| NULL 
Y  | D_y  |02/05/2012| USER1 
z  | D_z  |02/05/2015| NULL 
Y  | D_y  |02/05/2013| USER1 
z  | D_z  |02/05/2012| USER2 

我想file_nm，degree_nm，date_nm明智計數總文件，剩下的文件，完成

file total for x is 2 remaining for x is 1 completed file is 1 

我在多個單個查詢中獲得正確的值，但我想這個小號整個

select filenm,degree_name,date_name,COUNT(*) as total 
from sameTable 
group by filenm,degree_name,date_name 

select filenm,degree_name,date_name,COUNT(*) as remaining 
from sameTable 
group by filenm,degree_name,date_name,username 
having username is null 
select filenm,degree_name,date_name,COUNT(*) as completed 
from sameTable 
group by filenm,degree_name,date_name,username 
having username is not null 

O/P，我想

filenm,degree_name,date_name,total,remaining,completed 

Answer 1

總和案例：

select filenm, 
     degree_name, 
     date_name, 
     COUNT(*) as total, 
     sum(case when username is null then 1 else 0 end) as remaining, 
     sum(case when username is not null then 1 else 0 end) as complete 
from sameTable 
group by filenm,degree_name,date_name 

Answer 2

select filenm 
    ,degree_name 
    ,date_name 
    ,total = COUNT(*) 
    ,remaining = COUNT(DISTINCT CASE WHEN username is null THEN username ELSE NULL END) 
    ,completed = COUNT(DISTINCT CASE WHEN username is not null THEN username ELSE NULL END) 
from sameTable 
group by filenm,degree_name,date_name