在SQL中有一列的結果的百分比

我想要得到一個顯示Uniuque「Reasons」的結果，它們的數量以及它們總數的百分比。到目前爲止，我有在SQL中有一列的結果的百分比

SELECT DISTINCT Reason, 
     COUNT(Reason) AS Number, 
     CAST(COUNT(Reason) AS float)/CAST(COUNT(*) AS float) AS percentage 
FROM DeletedClients

但是，正如我發現COUNT（*）和COUNT（原因）給出相同的結果。所以我的基本問題是，當我在查詢中使用distinct時，如何獲得總行數？我正在使用SQL Server 2005

來源

2009-12-29 Scott Chamberlain

的SQL供應商 – 2009-12-29 22:49:09

SELECT Reason, 
     COUNT(Reason) AS Number, 
     CAST(COUNT(Reason) AS float)/CAST(t.Total AS float) AS percentage 
FROM DeletedClients, 
    (SELECT COUNT(*) As Total FROM DeletedClients) t 
GROUP BY Reason, Total

來源

2009-12-29 23:09:45

select reason, count(reason), 
     (count(reason)::float/(select count(reason) from reasons)::float) * 100 
     as percent 
from DeletedClients group by reason order by reason;

這就是我想出來的。我以postgresql特定的方式進行了投射，但您可以根據自己的需要進行調整。你需要使用group by。我剛好因爲我喜歡它添加的順序：P

來源

2009-12-29 22:53:56

我認爲你應該使用group by：


SELECT Reason, 
     COUNT(Reason) AS Number, 
     CAST(COUNT(Reason) AS float)/CAST(COUNT(*) AS float) AS percentage 
FROM DeletedClients 
GROUP BY Reason

來源

2009-12-29 22:54:03

這導致1所有行（SQL Server）的 – 2009-12-29 23:11:24

你是對的百分比我的壞 – 2009-12-29 23:26:29

用途：

SELECT x.reason, 
     x.num AS NUMBER, 
     CONVERT(x.num, float)/(SELECT CONVERT(COUNT(*), float) FROM DELETEDCLIENTS) AS PERCENTAGE 
    FROM (SELECT t.reason, 
       COUNT(*) 'num' 
      FROM DELETEDCLIENTS t 
     GROUP BY t.reason) x

來源

2009-12-29 22:55:56

這給0，以百分比的所有行。 – 2009-12-29 23:12:39

@Brian：正確 - 整數數學。 – 2009-12-30 02:10:03

您的查詢會出現問題，因爲它是。如果你想返回Reason列，

至於目標，COUNT（和其他聚合）忽略空值（如果你至少使用SQL Server），所以這個應該工作：。

DECLARE @TOTAL FLOAT 
SELECT @TOTAL = COUNT(1) 
FROM DeletedClients 

SELECT DISTINCT 
    Reason, 
    Cnt AS Number, 
    @TOTAL AS TotalRecords, 
    CAST(Cnt AS float)/@TOTAL AS percentage 
FROM (
    SELECT 
     Reason, 
     COUNT(*) AS Cnt 
    FROM DeletedClients 
    GROUP BY Reason 
) t 
GROUP BY 
    Reason, 
    Cnt

來源

2009-12-29 22:56:07

在SQL中有一列的結果的百分比

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