从mysql中的日期字段获取月份数据答案

【问题标题】：Month wise data fetch from date field in mysql从mysql中的日期字段获取月份数据
【发布时间】：2021-10-20 08:02:00
【问题描述】：

我有一个表名billing，我的表数据如下所示

id	site_name	billing_date	amount
1	abc	2021-01-15	100
2	abc	2021-02-15	80
3	abc	2021-03-15	120
4	abc	2021-04-15	110
5	abc	2021-05-15	105
6	abc	2021-06-15	90
7	abc	2021-07-15	106
8	abc	2021-08-15	70
9	xyz	2021-01-15	100
10	xyz	2021-02-15	90
11	xyz	2021-03-15	200
12	xyz	2021-04-15	300

我的预期结果会是这样的数据

site_name	Year	January	February	March	Arpil	May	June	July	August	September	October	November	December
abc	2021	100	80	120	110	105	90	106	70	0	0	0	0
xyz	2021	100	90	200	300	0	0	0	0	0	0	0	0

另外site_name,abc月份January只有一条记录，February和其他月份一样只有一条记录。我已经尝试了以下代码，但没有得到预期的输出

select site_name, YEAR(billing_date) as YearName, monthname(billing_date) as monthName, amount
    from bills
    group by site_name, YEAR(billing_date),monthname(billing_date),amount
    order by site_name;

请对如何获得我的预期输出提出任何建议

【问题讨论】：

modern-sql.com/use-case/pivot
@jarlh，非常感谢。我会按照您的建议尝试这种方式

标签： php mysql sql database

【解决方案1】：

根据@jarlh 的以下链接，我已经按照以下代码解决了我的问题。这对我和我想要的东西真的很有帮助。

SELECT site_name, YearName 
, SUM(CASE WHEN month =  1 THEN amount END) January      
, SUM(CASE WHEN month =  2 THEN amount END) February      
, SUM(CASE WHEN month =  3 THEN amount END) March      
, SUM(CASE WHEN month =  4 THEN amount END) April      
, SUM(CASE WHEN month =  5 THEN amount END) May      
, SUM(CASE WHEN month =  6 THEN amount END) June      
, SUM(CASE WHEN month =  7 THEN amount END) July      
, SUM(CASE WHEN month =  8 THEN amount END) August      
, SUM(CASE WHEN month =  9 THEN amount END) September      
, SUM(CASE WHEN month =  10 THEN amount END) October   
, SUM(CASE WHEN month =  11 THEN amount END) November      
, SUM(CASE WHEN month = 12 THEN amount END) December   
FROM (SELECT ems_table.electric_bills.* 
    , EXTRACT(YEAR  FROM last_billing_date) YearName              
    , EXTRACT(MONTH FROM last_billing_date) month           
    FROM ems_table.electric_bills) 
    alias_table  GROUP BY site_name, YearName ORDER BY site_name ASC;

【讨论】：