需要通过比较两个表来显示 Total Customer 的 MAX COUNT

Posted 2023-02-16

【中文标题】需要通过比较两个表来显示 Total Customer 的 MAX COUNT

【英文标题】：Need to show MAX COUNT of Total Customer by comparing two tables

【发布时间】：2021-10-27 23:36:54

【问题描述】：

目前客户总数来自 mq_billing 表，但我们需要从 mq_billing 和 mq_paymentlist 表中搜索并显示最大计数。对于 Total Customer，这两个表的列名称相同 Customer_Nbr。

这是我的 SQL：

SELECT b.Entity_Name, 
       b.`Total Customer`,
       b.`Invoice Amount`,
       p.`Online Payment`,
       p.`Cash Payment`,
       p.`Total Payment`
FROM (
  SELECT Entity_Name, 
         COUNT(Customer_Nbr) AS `Total Customer`,
         SUM(Invoice_Amount) AS `Invoice Amount`
  FROM mq_billing
  GROUP BY Entity_Name
) b INNER JOIN (
  SELECT Entity_Name, 
       SUM(CASE WHEN Payment_Mode = 'Online Payment' THEN Amount ELSE 0 END) AS `Online Payment`,
       SUM(CASE WHEN Payment_Mode = 'Cash' THEN Amount ELSE 0 END) AS `Cash Payment`,
       SUM(Amount) AS `Total Payment`
  FROM mq_paymentlist
  GROUP BY Entity_Name
) p ON b.Entity_Name = p.Entity_Name
ORDER BY b.Entity_Name;

【参考方案1】：

就像您在第一个子查询中选择 COUNT(Customer_Nbr) 一样，在第二个子查询中也选择它：

SELECT Entity_Name, 
       COUNT(Customer_Nbr) AS `Total Customer`,
       SUM(CASE WHEN Payment_Mode = 'Online Payment' THEN Amount ELSE 0 END) AS `Online Payment`,
       SUM(CASE WHEN Payment_Mode = 'Cash' THEN Amount ELSE 0 END) AS `Cash Payment`,
       SUM(Amount) AS `Total Payment`
FROM mq_paymentlist
GROUP BY Entity_Name

在主查询中使用GREATEST() 选择最大值：

SELECT b.Entity_Name, 
       GREATEST(b.`Total Customer`, p.`Total Customer`) AS `Total Customer`
.........................

【讨论】：

错误代码：1054。“字段列表”中的未知列“b.Total Customer”

你能帮我解决另一个问题吗？ ***.com/questions/68970325/…

INNER JOIN 仅获取常见的 Entity_Name，但我还需要获取不常见的 Entity_Name。请问可以修改吗？

@RaceTech 问题不在 cmets 部分提出。我的回答是关于您发布的问题。如果您有新要求，您可以发布一个新问题，说明您想要什么。

请查看新问题***.com/questions/68970325/…