替代子選擇在MySQL

Question

我的產品表提供這樣

Producer Category Quality 
113085  EIT  05 
113085  EIT  06 
113085  EIT  04 
113085  EIT  05 
113085  EIT  05 
116159  EIT  05 
116159  EIT  04 
116159  EIT  04 
110058  EIT  06 
121570  EIT  04 

我想瑟每個生產者相比，平均百分比所有生產者質量等級之間的分配。 像這樣：

Producer Category Quality  Totalpercent Producerpercent 
113085  EIT   05   40   60 
113085  EIT   06   20   20 
113085  EIT   04   40   20 

我有這樣的選擇做我想做的，但它周圍260.000記錄運行70-80秒，我的服務器上，這是很多:-)

你有任何提示加快這一點？

select 
Producer as Producer1, 
Category as Category1, 
Quality as 'Quality1', 

Round(((select count(*) from base where Category=Category1 and Quality=Quality1 and deliverydate >'2016-10-01')/ 
    (select count(*) from base where Category=Category1 and deliverydate >'2016-10-01') 
    *100),1) as 'Totalpercent', 

Round(((select count(*) from base where Category=Category1 and Quality=Quality1 and deliverydate >'2016-10-01' and Producer=Producer1)/ 
    ((select count(*) from base where Category=Category1 and deliverydate >'2016-10-01' and Producer=Producer1)) 
    *100),1) as 'Producerpercent' 

from base where deliverydate >'2016-10-01' and Producer=113085 group by Category1, Quality1 

Answer 1

我認爲你可以明確地簡化你的查詢。這是第一個開始：

SELECT 
    `Producer`, 
    `Category`, 
    `Quality`, 
    round(100*(SELECT COUNT(*) FROM base`subquery` WHERE subquery.Quality = mainquery.Quality)/
     (SELECT COUNT(*) FROM base),1) 
     AS 'Totalpercent', 
    round((100*COUNT(*))/ 
     (SELECT COUNT(*) FROM base WHERE `Producer`=113085),1) 
     AS 'Producerpercent' 
FROM base `mainquery` 
WHERE `Producer`=113085 
GROUP BY `Category`, `Quality` 

這減少了從屬子查詢的數量。

這裏比較：http://www.sqlfiddle.com/#!9/689ce/5