无论MySQL中是否有每月数据，如何显示一年中的所有月份答案

【问题标题】：How to show all months in year regardless if there is a data per month in MySQL无论MySQL中是否有每月数据，如何显示一年中的所有月份
【发布时间】：2017-03-07 20:00:15
【问题描述】：

我有一个表view_remit，每个月的第一天（E_FROM）到月底（E_TO）都有一个ID列表和它们各自的total_PBR。

|  ID  |  E_From  |   E_To   |Total_PBR|
|  01  |01/01/2016|03/31/2016|  1000   |
|  01  |08/01/2016|08/31/2016|  1000   |
|  02  |01/01/2016|01/31/2016|  3000   |
|  02  |02/01/2016|02/29/2016|  3000   |

我想要的是选择每个 ID 支付和不支付的所有月份。就像下面这个例子。

|  ID  |  E_From  |   E_To   |Total_PBR|
|  01  |01/01/2016|01/31/2016|  1000   |
|  01  |02/01/2016|02/29/2016|  1000   |
|  01  |03/01/2016|03/31/2016|  1000   |
|  01  |04/01/2016|04/30/2016|    0    |
|  01  |05/01/2016|05/31/2016|    0    |
|  01  |06/01/2016|06/30/2016|    0    |
|  01  |07/01/2016|07/31/2016|    0    |
|  01  |08/01/2016|08/31/2016|  1000   |
|  01  |09/01/2016|09/30/2016|    0    |
|  01  |10/01/2016|10/31/2016|    0    |
|  01  |11/01/2016|11/30/2016|    0    |
|  01  |12/01/2016|12/31/2016|    0    |

我在这里使用了另一个问题的代码MySQL monthly Sale of last 12 months including months with no Sale

SELECT ID, 
IF( MONTH( E_From ) =  1, Total_PBR, 0 ) AS  'Jan', 
IF( MONTH( E_From ) =  2, Total_PBR, 0 ) AS  'Feb', 
IF( MONTH( E_From ) =  3, Total_PBR, 0 ) AS  'Mar', 
IF( MONTH( E_From ) =  4, Total_PBR, 0 ) AS  'Apr', 
IF( MONTH( E_From ) =  5, Total_PBR, 0 ) AS  'May', 
IF( MONTH( E_From ) =  6, Total_PBR, 0 ) AS  'Jun', 
IF( MONTH( E_From ) =  7, Total_PBR, 0 ) AS  'Jul', 
IF( MONTH( E_From ) =  8, Total_PBR, 0 ) AS  'Aug', 
IF( MONTH( E_From ) =  9, Total_PBR, 0 ) AS  'Sep', 
IF( MONTH( E_From ) =  10, Total_PBR, 0 ) AS 'Oct', 
IF( MONTH( E_From ) =  11, Total_PBR, 0 ) AS 'Nov', 
IF( MONTH( E_From ) =  12, Total_PBR, 0 ) AS 'Dec', year(E_FROM) AS Year,
SUM(Total_PBR ) AS total_yearly
FROM view_remit
GROUP BY PEN, YEAR( E_From )
LIMIT 0 , 30

它有效，但它没有正确计算某些月份的 total_PBR。任何帮助表示赞赏。

【问题讨论】：

如果您愿意，请考虑遵循以下简单的两步操作： 1. 如果您还没有这样做，请提供适当的 CREATE 和 INSERT 语句（和/或 sqlfiddle），以便我们可以更容易复制问题。 2. 如果您尚未这样做，请提供与步骤 1 中提供的信息相对应的所需结果集。
GROUP BY 中的“笔”是什么？它应该是“ID”吗？

标签： mysql date sum

【解决方案1】：

试试这个：

SELECT ID, 
SUM(IF( MONTH( E_From ) =  1, Total_PBR, 0 )) AS  'Jan', 
SUM(IF( MONTH( E_From ) =  2, Total_PBR, 0 )) AS  'Feb', 
SUM(IF( MONTH( E_From ) =  3, Total_PBR, 0 )) AS  'Mar', 
SUM(IF( MONTH( E_From ) =  4, Total_PBR, 0 )) AS  'Apr', 
SUM(IF( MONTH( E_From ) =  5, Total_PBR, 0 )) AS  'May', 
SUM(IF( MONTH( E_From ) =  6, Total_PBR, 0 )) AS  'Jun', 
SUM(IF( MONTH( E_From ) =  7, Total_PBR, 0 )) AS  'Jul', 
SUM(IF( MONTH( E_From ) =  8, Total_PBR, 0 )) AS  'Aug', 
SUM(IF( MONTH( E_From ) =  9, Total_PBR, 0 )) AS  'Sep', 
SUM(IF( MONTH( E_From ) =  10, Total_PBR, 0 )) AS 'Oct', 
SUM(IF( MONTH( E_From ) =  11, Total_PBR, 0 )) AS 'Nov', 
SUM(IF( MONTH( E_From ) =  12, Total_PBR, 0 )) AS 'Dec', 
year(E_FROM) AS Year,
FROM view_remit
GROUP BY ID, YEAR( E_From )

如果您每个月只有一条数据记录，请忽略 SUM() 函数

【讨论】：

【解决方案2】：

您可以参考此查询并根据您的目的对其进行修改。我创建了一个包含以下数据的测试表：

select * from test;
+----+---------------------+--------+
| id | pay_date            | salary |
+----+---------------------+--------+
|  1 | 2015-01-01 00:00:00 |   5000 |
|  2 | 2015-02-01 00:00:00 |   6000 |
|  3 | 2015-05-01 00:00:00 |   5000 |
|  4 | 2015-09-01 00:00:00 |   8000 |
+----+---------------------+--------+

现在运行以下查询：

SELECT months.monthname, coalesce(payments.salary, 0) FROM
(
  SELECT 'January'   monthname, 1  month_num UNION 
  SELECT 'February'  monthname, 2  month_num UNION 
  SELECT 'March'     monthname, 3  month_num UNION 
  SELECT 'April'     monthname, 4  month_num UNION 
  SELECT 'May'       monthname, 5  month_num UNION 
  SELECT 'June'      monthname, 6  month_num UNION 
  SELECT 'July'      monthname, 7  month_num UNION 
  SELECT 'August'    monthname, 8  month_num UNION 
  SELECT 'September' monthname, 9  month_num UNION 
  SELECT 'October'   monthname, 10 month_num UNION
  SELECT 'November'  monthname, 11 month_num UNION 
  SELECT 'December'  monthname, 12 month_num
) months
LEFT JOIN(
  SELECT monthname (pay_date) monthname, salary FROM test
) payments
ON (months.monthname=payments.monthname)
ORDER BY months.month_num;

这将显示这些结果：

+-----------+------+
| monthname | pay  |
+-----------+------+
| January   | 5000 |
| February  | 6000 |
| March     |    0 |
| April     |    0 |
| May       | 5000 |
| June      |    0 |
| July      |    0 |
| August    |    0 |
| September | 8000 |
| October   |    0 |
| November  |    0 |
| December  |    0 |
+-----------+------+
12 rows in set (0.00 sec)

【讨论】：