在SQL中划分两个查询然后划分为

我正在寻找新账户和所有账户之间的利率变化，我列出了以下两个查询。我需要将AllAccounts除以NewAccounts，并在同一个查询中按城镇分组。由于在SQL中划分两个查询然后划分为

SELECT DISTINCT Count(NewAccounts), Town 
FROM (SELECT Stuff) 
WHERE (Newaccounts) 
Group By Town 
; 
SELECT DISTINCT Count(AllAccounts), Town 
FROM (SELECT DifferentSTUFF) 
WHERE (AllAccounts) 
Group By Town

来源

2014-02-28 ColorfulWind

你需要重写你的查询，子查询和将它们连接在一起：

SELECT CAST(na.NewAccounts AS FLOAT)/aa.AllAccounts 
FROM ( SELECT Count(NewAccounts) AS NewAccounts, Town 
      FROM (SELECT Stuff) 
      WHERE (Newaccounts) 
      GROUP BY Town 
     ) na 
     INNER JOIN 
     ( SELECT Count(AllAccounts) AS AllAccounts, Town 
      FROM (SELECT DifferentSTUFF) 
      WHERE (AllAccounts) 
      GROUP BY Town 
     ) aa 
      ON aa.Town = na.Town;

注：我从两个查询中删除DISTINCT，因为它是多余的。浮动在NewAccounts上的转换是为了避免将结果整数除法隐式转换回整数。

您可能需要更改此略有不同数据的每个查询，即可用性，如果你不会总是有一个镇的新帐户，将更好的写法如下结果：

SELECT CAST(COALESCE(na.NewAccounts, 0) AS FLOAT)/aa.AllAccounts 
FROM  
     ( SELECT Count(AllAccounts) AS AllAccounts, Town 
      FROM (SELECT DifferentSTUFF) 
      WHERE (AllAccounts) 
      GROUP BY Town 
     ) aa 
     LEFT JOIN 
     ( SELECT Count(NewAccounts) AS NewAccounts, Town 
      FROM (SELECT Stuff) 
      WHERE (Newaccounts) 
      GROUP BY Town 
     ) na 
      ON aa.Town = na.Town

来源

2014-02-28 14:53:04 GarethD

这工作完美。谢谢。我没有内在的联合征服他们。 – ColorfulWind

如何将小数减少到两个地方？（我试图用decimal替换Float并且转换为cast） – ColorfulWind

只需要输出完整结果以及分母或分子：CAST（CAST（COALESCE（na.NewAccounts，0）AS FLOAT）/ aa.AllAccounts AS DECIMAL（10，2））' – GarethD

在SQL中划分两个查询然后划分为

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