Question

我正在尝试根据代码的CASES部分中提到的三种不同情况来计算订单百分比。当我运行代码时，每种情况下的值都将百分比值显示为“ 1”。我认为问题出在代码的最后一行，我该如何解决？

SELECT DATEDIFF_GRP,ROUND(COUNT(DISTINCT(ORDER_ID))*100/(SELECT COUNT(DISTINCT(A.ORDER_ID)) FROM A),2)||'%' AS PERCENTAGE_ORDERS  FROM A
GROUP BY DATEDIFF_GRP ;

Answer 1

MySQL通常不使用||进行字符串连接，您必须启用一些非默认选项才能实现此功能。

正在发生的事情是MySQL相反将||解释为逻辑OR运算符。为完全避免此问题，请考虑使用CONCAT函数。

SELECT
    DATEDIFF_GRP,
    CONCAT(100 * ROUND(COUNT(DISTINCT(ORDER_ID)) /
        (SELECT COUNT(DISTINCT(A.ORDER_ID)) FROM A), 2), '%') AS PERCENTAGE_ORDERS
FROM A;

您可以还可以通过启用ANSI模式来解决您的问题，但是正如下面所评论的，很少有MySQL用户在此模式下使用数据库。

Answer 2

您可以在下面尝试-在我看来，您尝试使用||运算符进行连接，但是mysql支持concat()函数而不是||运算符

WITH A AS (SELECT OS.ACTUAL_DISPATCH_DATE,OT.ORDER_ID,OT.First_msg_date,datediff(OT.First_msg_date,OS.ACTUAL_DISPATCH_DATE) AS DATEDIFF,
CASE WHEN  datediff(OT.First_msg_date,OS.ACTUAL_DISPATCH_DATE)<=0 THEN 'OTIF' 
    WHEN  datediff(OT.First_msg_date,OS.ACTUAL_DISPATCH_DATE)=1 THEN 'OTIF+1'
    WHEN  datediff(OT.First_msg_date,OS.ACTUAL_DISPATCH_DATE)=2 THEN 'OTIF+2'
    ELSE  'OTIF+>2'
END as DATEDIFF_GRP
FROM order_shipment OS RIGHT JOIN 
(SELECT ORDER_ID,MIN((str_to_date(SUBSTRING(MESSAGE,INSTR(MESSAGE,'2'),10),'%Y-%m-%d'))) AS First_msg_date 
FROM ORDER_TIMELINE
GROUP BY ORDER_ID ) OT
ON (OS.ORDER_ID=OT.ORDER_ID)) 
SELECT DATEDIFF_GRP,concat(ROUND(COUNT(DISTINCT(ORDER_ID))*100/(SELECT COUNT(DISTINCT(A.ORDER_ID)) FROM A),2),'%') AS PERCENTAGE_ORDERS  
FROM A
GROUP BY DATEDIFF_GRP ;

在SQL中计算百分比时出错

2 个答案: