在SQL中劃分兩個查詢然後劃分爲

我正在尋找新賬戶和所有賬戶之間的利率變化，我列出了以下兩個查詢。我需要將AllAccounts除以NewAccounts，並在同一個查詢中按城鎮分組。由於在SQL中劃分兩個查詢然後劃分爲

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

來源

2014-02-28 ColorfulWind

你需要重寫你的查詢，子查詢和將它們連接在一起：

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：我從兩個查詢中刪除DISTINCT，因爲它是多餘的。浮動在NewAccounts上的轉換是爲了避免將結果整數除法隱式轉換回整數。

您可能需要更改此略有不同數據的每個查詢，即可用性，如果你不會總是有一個鎮的新帳戶，將更好的寫法如下結果：

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

來源

2014-02-28 14:53:04 GarethD

這工作完美。謝謝。我沒有內在的聯合征服他們。 – ColorfulWind

如何將小數減少到兩個地方？（我試圖用decimal替換Float並且轉換爲cast） – ColorfulWind

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

在SQL中劃分兩個查詢然後劃分爲

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