如何分隔在select語句中求和的兩列？

下面的這條語句爲我提供了一些我需要的數據。如何分隔在select語句中求和的兩列？

select TankName, COUNT(*) as Tanks, sum(Battles) as Battles, 
    SUM(victories) as Victories 
from MemberTanks 
where Tier = 9 and Class = 'Medium' 
group by TankName 
order by Tanks desc

我想在結果集中顯示勝利的百分比，但我不知道該怎麼做。我試過...

select TankName, COUNT(*) as Tanks, sum(Battles) as Battles, 
    SUM(victories) as Victories, SUM(Victories)/SUM(Battles) as Percentage 
from MemberTanks 
where Tier = 9 and Class = 'Medium' 
group by TankName 
order by Tanks desc

...但百分比在每一行回來爲「0」。

我該如何最好地得到這個值？

來源

2011-06-10 Sailing Judo

什麼是Vicotires和Battles的數據類型？另外，他們有沒有任何空值。 – YetAnotherUser 2011-06-10 18:04:13

沒有空值。他們都是「int」 – 2011-06-10 18:05:04

啊......我想我知道這是怎麼回事。我敢打賭，這是一個投射問題。 – 2011-06-10 18:05:45

當你計算百分比柱因爲SUM（X）是返回一個INT值，其結果是得到地板，因此與像1.0十進制值返回0作爲地板的結果

乘以SUM（勝利）（以便將一個操作數轉換爲十進制/數字），然後您將得到正確的結果。或者也

SELECT TankName, 
    COUNT(*) as Tanks, 
    SUM(Battles) as Battles, 
    SUM(victories) as Victories, 
    SUM(victories) * 1.0/ SUM(Battles) AS Percentage 
FROM MemberTanks 
WHERE Tier = 9 
    AND Class = 'Medium' 
GROUP BY TankName 
ORDER BY Tanks desc

，如果您使用的是SQL Server 2005的上方，你可以使用CTE像下面減少calculations.computations：

試試這個

WITH qry AS 
(
    SELECT TankName, 
     COUNT(*) as Tanks, 
     SUM(Battles) as Battles, 
     SUM(victories) as Victories 
    FROM MemberTanks 
    WHERE Tier = 9 
     AND Class = 'Medium' 
    GROUP BY TankName 
) 
SELECT a.*, 
       Victories * 1.0/Battles AS Percentage 
    FROM qry a 
ORDER BY Tanks DESC

來源

2011-06-10 18:06:25 Chandu

試試這個 -

SUM(Convert(float, Battles))/ Sum(Convert(float, Victories))

見MSDN:

返回優先級較高的參數的數據類型。有關更多信息，請參閱數據類型優先級（Transact-SQL）。

如果整數被除數通過除以整數除數，結果是整數，其具有任何小數部分的結果截斷的。

來源

2011-06-10 18:07:32 YetAnotherUser

如何分隔在select語句中求和的兩列？

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