如何将不同列中的列值分组并在不同列中显示答案

【问题标题】：How to group column value in different column and display it in different column如何将不同列中的列值分组并在不同列中显示
【发布时间】：2021-11-08 09:44:50
【问题描述】：

我有一个名为公司和公司对客户的回应的专栏。我需要选择具有三个值“已关闭”、“以解释关闭”和“以非货币救济关闭”的公司和公司对客户的响应。

我必须将其显示为 4 列公司，“关闭并解释”与“关闭”值，“关闭并解释”与“关闭并解释”值，“关闭并解释”与“关闭非货币救济” ' 价值。这就是我想要的

有谁知道我需要使用什么命令将其显示到 4 个不同的列中？

这是我目前的语法。它已经按公司分组，但我没有将其显示到不同的列中

select company, count(`Company Response to Consumer`)
from consumercomplaints
where `Company Response to Consumer` in ('Closed', 'Closed with explanation', 'Closed with non-monetary relief')
group by company

这是当前的输出

【问题讨论】：

标签： mysql sql group-by mariadb

【解决方案1】：

您确实需要条件聚合。在 MySQL 中，这可以通过使用 sum(<boolean expression>) 进行最简单的处理：

select company,
       sum(`Company Response to Consumer` = 'Closed') as num_closed,
       sum(`Company Response to Consumer` = 'Closed with explanation') as num_closed_with_explanation,
       sum(`Company Response to Consumer` = 'Closed with non-monetary relief') as num_closed_with_nonmonetary_relief
from consumercomplaints
where `Company Response to Consumer` in ('Closed', 'Closed with explanation', 'Closed with non-monetary relief')
group by company;

【讨论】：

【解决方案2】：

您可以在此处使用 case 表达式来创建列

select 
    company, 
    SUM(CASE
        WHEN `Company Response to Consumer`='Closed' THEN 1
        ELSE 0
    END) as `Closed`,
    SUM(CASE
        WHEN `Company Response to Consumer`='Closed with explanation' THEN 1
        ELSE 0
    END) as `Closed with explanation`,
    SUM(CASE
        WHEN `Company Response to Consumer`='Closed with non-monetary relief' THEN 1
        ELSE 0
    END) as `Closed with non-monetary relief`
from consumercomplaints
where `Company Response to Consumer` in ('Closed', 'Closed with explanation', 'Closed with non-monetary relief')
group by company

注意。 where 子句在这里是可选的，因为 case 表达式提供了一个 0/1 值，当求和时，它会计算数据集中出现的次数。

让我知道这是否适合你。

【讨论】：