後，選擇平均

在我目前的表我試圖根據COMP_NAME獲得列的平均值，以下是輸出後，選擇平均

"Comp_Name"   "No_of_Rows" "Column1_Avg" "Column2_Avg" "Column3_Avg" 
    "Company1 Pty Ltd" "291"   "39"   "60"   "0" 
    "Company1 Pty."  "1699"   "23"   "76"   "0" 
    "Company2 Ltd"  14335"   "6"    "82"   "10" 
    "Company2 "   "4335"   "60"   "8"    "2" 
    "Company3 Pty Ltd" "767"   "22"   "77"   "0" 
    "Company3"   "1628"   "16"   "82"   "1"

是可以平均「的公司1私人有限公司」和「MySQL的命名列的值Company1 Pty。「（和其他公司），但添加行數？

我的選擇查詢是下面，基本上它是基於一定的值計算平均值，並根據公司名稱分組可在表

SELECT Comp_Name,count(*) as No_of_Rows, 
    CAST( (COUNT(CASE WHEN Column1 < 500 then 1 else NULL end)/COUNT(mytable.ID)) * 100 AS CHAR(2))+'%' as Column1_Avg, 
    CAST( (COUNT(CASE WHEN (Column1 < 30000 AND Column1 > 500) then 1 else NULL end)/COUNT(mytable.ID)) * 100 AS CHAR(2))+'%' as Column2_Avg, 
    CAST( (COUNT(CASE WHEN (Column1 > 30000) then 1 else NULL end)/COUNT(mytable.ID)) * 100 AS CHAR(2))+'%' as Column3_Avg 
    FROM mytable 
    GROUP BY Comp_Name desc

預期輸出：

"Comp_Name"   "No_of_Rows" "Column1_Avg" "Column2_Avg" "Column3_Avg" 
    "Company1"   "1990"   "31"   "68"   "0" 
    "Company2"   "18670"   ".."   ".."   "6" 
    "Company3"   "2395"   ".."   ".."   ".."

我可以使用某種具有company_name列表的參考表並且它的替換？

來源

2012-05-18 Linus

如果你想只取第一個字在你GROUP BY條款，你可以使用：

 
GROUP BY CASE LOCATE(' ', Comp_Name) WHEN 0 THEN Comp_Name ELSE LEFT(Comp_Name, LOCATE(' ', Comp_Name)) END

然後，如果你想建立一個參考表，這樣的查詢應該是罰款：

 
SELECT DISTINCT Comp_Name, CASE LOCATE(' ', Comp_Name) WHEN 0 THEN Comp_Name ELSE LEFT(Comp_Name, LOCATE(' ', Comp_Name)) END AS Simple_Comp_Name 
FROM mytable 
ORDER BY Simple_Comp_Name

來源

2012-05-18 06:10:47

謝謝。我也試過INNER JOIN，似乎工作正常。 – Linus

後，選擇平均

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