See this SQLFiddle

Question

我有一张桌子，问题已通过或未通过。

我只需要一个SQL查询来查找问题总数中问题1的失败百分比。

我正在尝试这个，但这会出现语法错误 -

$CA001 = "COUNT(CA001Result WHERE CA001Result = "Fail") / COUNT(CA001Result)) From Datable";

正如我所说，总的菜鸟，它是MYSQL btw。

我不需要隔离产品的％结果，到目前为止我已经得到了这个，并且尝试过GROUP by Product但是没有用，有什么想法吗？

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

再看一遍，我需要在下面的地方插入一个WHERE Product ='Product'，但不太明白放在哪里，因为下面的内容不起作用：

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

Answer 1

假设这是你的表：

ID     Answer
-------------
 1  ,  'pass'
 2  ,  'pass'
 3  ,  'fail'
 4  ,  'fail'
 5  ,  'fail'
 6 ,   'fail'

所以你需要使用这样的子查询：

SELECT 100 * 
(SELECT COUNT(answer) FROM t WHERE answer='fail')/COUNT(answer)
AS Fail_percent FROM t;

或者您可以将COUNT与CASE一起使用，如下所示：

SELECT 100 * 
COUNT(CASE WHEN answer = 'fail' THEN 1 ELSE NULL END)/COUNT(answer)
AS Fail_percent FROM t;

或者您可以将SUM与CASE一起使用，如下所示：

SELECT 100 * 
SUM(CASE WHEN answer = 'fail' THEN 1 ELSE 0 END)/COUNT(answer)
AS Fail_percent FROM t;

或者您可以使用SUM而不使用CASE（仅限MySQL）：

SELECT 100 * 
SUM(answer = 'fail')/COUNT(answer)
AS Fail_percent FROM t;

计算表中String值的百分比

1 个答案:

See this SQLFiddle