如何根據兩列找到一列的數量

Question

如何根據「競爭」和「用戶」列獲得最後一列？以下查詢給出錯誤！

SELECT DISTINCT COUNT(*) AS countofcomments 
 
FROM k 
 
GROUP BY competition, user

Answer 1

我不知道的是，一個很好的做法，你想實現的，在考慮到結果集，你可以嘗試這樣的

CREATE TABLE #Example(
     [competition]  [nvarchar](50) NULL,  
     [user] [nvarchar](50) NULL, 
     [comments] nvarchar(50) NOT NULL, 
) 
GO 

INSERT #Example ([competition],[user], [comments]) VALUES ('INDIA','CHENNAI','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('INDIA','KOCHI','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('INDIA','BANGLORE','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('INDIA','HYDERABAD','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('US','MAIAMI','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('US','SANFRANC','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('US','MOUNT','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('US','LOSANGELS','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('UK','MANCHESTER','ssss') 
INSERT #Example ([competition],[user], [comments]) VALUES ('UK','CHELSEA','ssss') 

SELECT * from (
SELECT * FROM #Example 
) tab1 join 

(
SELECT [competition] , count([comments])count FROM #Example 
group by [competition] 
) tab2 on tab1.[competition]= tab2.[competition] 


DROP table #Example 

Answer 2

東西

您可以使用窗口功能執行此操作：

SELECT *, COUNT(*) OVER(PARTITION BY competition, user) as [Count of comments] 
FROM k