從mySQL查詢中收集兩個單獨的列結果

Question

我有兩個包含類似數據的數據庫表 - 其中一個是進程完成的工作量，另一個是該進程發生的錯誤數量。

我想顯示正確的第一次工作的百分比。

我通過工藝計算的項目數查詢：

SELECT Counter.Process, count(Counter.Process) AS count 
          FROM Counter WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
          GROUP BY Counter.Process 
          ORDER BY count DESC 

上面給了我類似的列表：

Process | count 
------------------- 
Process A | 40 
Process B | 32 
Process C | 102 
Process D | 23 

我有第二個表與它相同的字段用於記錄錯誤，稱爲「錯誤」。

通過使用相同的查詢（但明顯改變表名），我可以得到一個進程和錯誤的列表。

我想要做的是創建一個PHP網頁，顯示每個進程的錯誤百分比。

我的問題是，如果我分別創建兩個查詢，當我使用PHP Where循環遍歷它們時，我不知道如何使計算顯示百分比。

我試着在兩個SQL查詢之間使用UNION，但是我無法讓它顯示出針對該過程的兩個不同的計數讀數。

理想情況下，我想一個方法來顯示這樣的數據：

Process | Counter.count | Errors.count 
Process A  40    2 
Process B  32    0 
Process C  102    18 
Process D  23    8 

我真的很感激任何意見/建議，我怎麼能做到這一點 - 如果你需要我的數據庫的詳細信息表，請讓我知道

感謝您閱讀

小號

Answer 1

你可以使用子查詢：

SELECT Counter.Process, count(Counter.Process) AS Count, 
     (SELECT count(Errors.Process) 
     FROM Errors 
     WHERE Process=Counter.Process 
      AND (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59')) AS Errors 
          FROM Counter WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
          GROUP BY Counter.Process 
          ORDER BY count DESC 

Regards， Neil。

Answer 2

我沒有運行它，所以可能會有錯誤。你可以使兩個選擇，和左連接的結果：

select s.process, s.success_count, e.error_count 
from 
(SELECT Counter.Process as process, count(Counter.Process) AS success_count 
FROM Counter 
WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
GROUP BY Counter.Process 
) s left join 
(SELECT Errors.Process, count(Errors.Process) AS error_count 
     FROM Errors 
     WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
     GROUP BY Errors.Process 
) e 
on (s.Process = e.process) 

Answer 3

我個人更喜歡來用PHP執行這樣的情況，因爲它混淆了我少，所以我將解釋如何，我認爲我會做它在PHP（我說「想」，因爲我可能不知道一些關於你的數據庫結構或系統規範，這將使我的事情，否則）：

$rows = array(); 
$res = mysql_query('SELECT Counter.Process, count(Counter.Process) AS count 
         FROM Counter WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
         GROUP BY Counter.Process 
         ORDER BY count DESC'); 
while ($arr = mysql_fetch_assoc($res)) 
{ 
    $rows[] = $arr; 
} 

$res2 = mysql_query('SELECT Errors.Process, count(Errors.Process) AS count 
         FROM Counter WHERE (TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59') 
         GROUP BY Errors.Process 
         ORDER BY count DESC'); 
while ($arr2 = mysql_fetch_assoc($res2) 
{ 
    for ($i=0; $i<count($rows); $i++) 
    { 
     if ($arr2["Process"] == $data[$i]["process"]) 
     { 
      break; 
     } 
     //Do your functions with $arr and $data[$i] at this point... 
    } 
} 

Answer 4

沒有一個子查詢做它應該是簡單的：

SELECT 
    Counter.Process 
    , COUNT(Counter.Process) AS ProcessCount 
    , COUNT(Errors.Process) AS ProcessErrors 
FROM 
    Counter 
    LEFT JOIN 
    Errors 
    ON Counter.Process = Errors.Process 
WHERE 
    Counter.TIME BETWEEN '2012-07-01 00:00:00' AND '2012-07-06 23:59:59' 
GROUP BY 
    Counter.Process 

您可以對這兩個查詢進行解釋，以查看哪些數據最適合您的數據。

-edit：我已將它更改爲LEFT JOIN，因此如果進程沒有錯誤，則不會錯過行。