Calculating Percentage within MYSQL query based on conditions

问题

hope you can help, this is driving me up the wall

I need to calculate the percentage of times a question has been failed, but this needs to be narrowed down by the geographical area, and product these questions are being asked against.

I have :

$CA002 = "( SELECT ROUND(100 *  (SELECT count(CA002Result) from Data_Table where (CA002Result='Fail'))/count(CA002Result),2) from Data_Table) AS 'CA002 %'";

Which 'works' but just calculates against the whole set of records as an 'overall'

I'm trying :

$CA001 = "( SELECT ROUND(100 *  (SELECT count(CA001Result) from Data_Table where (CA001Result='Fail' AND Area ='$Area'))/count(CA001Result) from Data_Table WHERE (Area='$Area'),2) AS 'CA001 %'";

And Also :

$CA001 = "( SELECT ROUND(100 * (SELECT count(CA001Result ) from Data_Table where (CA001Result='Fail' AND Product='$product' AND Area='$Area'))      
    /     count(CA001Result WHERE Product = '$product' AND Area='$Area'),2) from Data_Table) AS 'CA001 %'";

Also Trying this, but get a MYSQL syntax Error.

$CA001 = "( SELECT ROUND(100 *  (SELECT count(CA001Result) from Data_Table where (CA001Result='Fail'))/ (SELECT (count(CA001Result) from Data_Table WHERE (Area='$Area')),2) AS 'CA001 %')";

and am just getting errors no matter what I try, I just can't seem to work out what I need to put where.

TRied the below answer:

$CA001 = "(SELECT 100 * SUM(IF(CA001Result='Fail', 1, 0)) / COUNT(CA001Result) as 'CA001 %' WHERE  Area='$Area')";

$CA002 = "( SELECT ROUND(100 *  (SELECT count(CA002Result) from Data_Table where (CA002Result='Fail'))/count(CA002Result),2) from Data_Table) AS 'CA002 %'";

but am getting the below as an error:

MySQL ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' ( SELECT ROUND(100 * (SELECT count(CA002Result) from Data_Table where (CA002Re' at line 1

Any help GREATLY appreciated, thankyou.

Edit - Cracked it using :

$CA001 ="ROUND ((SELECT 100 * SUM(IF(CA001Result='Fail', 1, 0)) / COUNT(CA001Result) 
FROM Data_Table
WHERE  Area='$Area'),2) as 'CA001 %'";

Thanks so much for the help!

回答1:

Try this

SELECT 100 * SUM(IF(CA001Result='Fail', 1, 0)) / COUNT(CA001Result) as 'CA002 %'
FROM Data_Table
WHERE '$product' AND Area='$Area'

回答2:

I'm only guessing your model, but you should try this pattern:

SELECT
    Area,
    Product,
    COUNT(*) as total,
    SUM(CA002Result='Fail') as total_fail,
    SUM(CA002Result='Fail') / COUNT(*) as 'CA002 %'
FROM Data_Table
GROUP BY Area, Product;

来源：https://stackoverflow.com/questions/12173248/calculating-percentage-within-mysql-query-based-on-conditions

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mysql

subquery