如何根據列值獲取百分比？

Question

更新05/18/15

在列上列有客戶名稱。我怎樣才能得到一個客戶每個日期的百分比？例如

CustomerName  Date 
    Sam    04/29/15 
    Joy    04/29/15 
    Tom    04/29/15 
    Sam    04/29/15 
    Oly    04/29/15 
    Joy    04/29/15 
        04/29/15 
    Sam    04/29/15 
        04/29/15 
    Sam    04/29/15 
    Oly    04/29/15 
    Sam    04/29/15 
    Oly    04/30/15 
    Joy    05/01/15 

發現我的列有12條，其中2個是空白，但他們不會指望的比例，只是有名字的人。我想知道Sam佔總數的百分比是多少（在這個例子中是10條記錄，所以Sam％是50）。

查詢應該返回

Date    Percentage 
04/29/15   50 
04/30/15   0 
05/01/15   0 

更新

我真的不關心其他的客戶，所以讓我們把他們當作一個。只需要知道總列表中Sam的百分比。

任何幫助將非常感激。由於

Answer 1

每個人都好像是用子查詢或派生表。這應該表現良好，並且很容易遵循。試試看：

DECLARE @CustomerName VARCHAR(5) = 'Sam'; 

SELECT [Date], 
     @CustomerName AS CustomerName, 
     percentage = CAST(CAST(100.0 * SUM(CASE WHEN CustomerName = @CustomerName THEN 1 ELSE 0 END)/COUNT(*) AS INT) AS VARCHAR(20)) + '%' 
FROM @yourTable 
WHERE CustomerName != '' 
GROUP BY [Date] 

結果：

Date  CustomerName percentage 
---------- ------------ --------------------- 
2015-04-29 Sam   50% 
2015-04-30 Sam   0% 
2015-05-01 Sam   0% 

Answer 2

，你會做這樣的事情

SELECT (COUNT(*) * 100)/(SELECT COUNT(*) FROM Customer WHERE CustomerName <> '' AND Date = '04/29/15') 
FROM Customer 
WHERE CustomerName = 'Sam' 
    AND Date = '04/29/15' 

如果你想獲得count每日期，你可以使用這個

SELECT T.Date,((ISNULL(CustomerCount,0) * 100)/TotalCount) 
FROM 
(
SELECT COUNT(*) as TotalCount,Date 
FROM Customer 
WHERE CustomerName <> '' 
GROUP BY Date 
)T 
LEFT JOIN 
(
SELECT COUNT(*) 
FROM Customer 
WHERE CustomerName = 'Sam' 
GROUP BY Date 
)C 
ON T.Date = C.Date 

Answer 3

你可以試試這個：

select name, date, (100.0 * count(*))/
    (select count(*) from table t2 
    where name is not null and name <> '' and t2.date = t1.date) 
from table t1 
where name is not null and name <> '' 
group by name, date 

Answer 4

對於所有用戶

SELECT 
     (COUNT(*) * 100)/(SELECT COUNT(*) FROM Customer WHERE CustomerName <> '') as [percent], 
     CustomerName 
    FROM Customer group by CustomerName 

爲specifice用戶

SELECT 
    (COUNT(*) * 100)/(SELECT COUNT(*) FROM Customer WHERE CustomerName <> '') as [percent], 
    CustomerName 
FROM Customer where CustomerName ='Sam' 

Answer 5

你可以計算出在子查詢每人+天數：

select Date 
,  CustomerName 
,  100.0 * cnt/sum(cnt) over (partition by date) 
from (
     select Date 
     ,  CustomerName 
     ,  count(*) cnt 
     from table1 
     where CustomerName <> '' 
     group by 
       Date 
     ,  CustomerName 
     ) t1 

此打印：

Date     CustomerName 
----------------------- ------------ --------------------------------------- 
2015-04-29 00:00:00.000 Joy   20.000000000000 
2015-04-29 00:00:00.000 Oly   20.000000000000 
2015-04-29 00:00:00.000 Sam   50.000000000000 
2015-04-29 00:00:00.000 Tom   10.000000000000 

(4 row(s) affected)