Question

我有一个表（帐户），其中包含帐户组和帐户的连接日期，以及其他字段。使用MySQL版本5.5.35-cll。

基本上我正在尝试做的是计算每个帐户组每个月发生的“注册”数量。（不仅是每月的总金额 - 需要知道每个帐户组每月发生的注册数量）。

所以结果看起来像这样：

intended results http://imageshack.com/a/img842/9105/drh9.gif

我尝试了一些不同的方法，但只是成功地获得了我需要的一个月，而不是一年中的所有月份。当我尝试使用SUM时，它看起来像是在工作，但它没有按预期工作 - 似乎它认为每组每月最多注册1次，而实际上至少有4或5个一些团体。

这是我最近（失败）尝试使用SUM：

SELECT accountgroup, 
SUM( IF( MONTH =1, numRecords, 0 ) AND YEAR=2014) AS  'January', 
SUM( IF( MONTH =2, numRecords, 0 ) AND YEAR=2014) AS  'February', 
SUM( IF( MONTH =3, numRecords, 0 ) AND YEAR=2014) AS  'March', 
SUM( IF( MONTH =4, numRecords, 0 ) AND YEAR=2014) AS  'April', 
SUM( IF( MONTH =5, numRecords, 0 ) AND YEAR=2014) AS  'May', 
SUM( IF( MONTH =6, numRecords, 0 ) AND YEAR=2014) AS  'June', 
SUM( IF( MONTH =7, numRecords, 0 ) AND YEAR=2014) AS  'July', 
SUM( IF( MONTH =8, numRecords, 0 ) AND YEAR=2014) AS  'August', 
SUM( IF( MONTH =9, numRecords, 0 ) AND YEAR=2014) AS  'September', 
SUM( IF( MONTH =10, numRecords, 0 ) AND YEAR=2014) AS  'October', 
SUM( IF( MONTH =11, numRecords, 0 ) AND YEAR=2014) AS  'November', 
SUM( IF( MONTH =12, numRecords, 0 ) AND YEAR=2014) AS  'December', 
SUM( numRecords ) AS total
FROM (
SELECT accountgroup, MONTH( joineddate ) AS MONTH, YEAR( joineddate ) AS YEAR, COUNT( * ) AS numRecords
FROM accounts 
WHERE accountgroup <>''
GROUP BY accountgroup, MONTH, YEAR) AS SubTable1
GROUP BY accountgroup");

任何人都可以告诉我该怎么做？我很难过:(
提前感谢您的帮助。

Answer 1

你非常接近。您需要将year条件放在if内。例如：

SUM(IF(MONTH = 1 AND YEAR = 2014, numRecords, 0)) AS January, 
SUM(IF(MONTH = 2 AND YEAR = 2014, numRecords, 0)) AS February, 
. . .

您不需要最后的括号。因此，查询应如下所示：

SELECT accountgroup, 
       SUM(IF(MONTH = 1 AND YEAR = 2014, numRecords, 0)) AS January, 
       SUM(IF(MONTH = 2 AND YEAR = 2014, numRecords, 0)) AS February, 
       . . . 
       SUM( numRecords ) AS total
FROM (SELECT accountgroup, MONTH( joineddate ) AS MONTH, YEAR( joineddate ) AS YEAR, COUNT( * ) AS numRecords
      FROM accounts 
      WHERE accountgroup <>''
      GROUP BY accountgroup, MONTH, YEAR
     ) AS SubTable1
GROUP BY accountgroup";

此外，不要对应该是列名或表名的内容使用单引号。在这种情况下，您不需要转义这些名称。使用双引号或反引号。仅对字符串和日期常量使用单引号。

计算每个帐户组的记录数量，其中加入日期=每月

1 个答案: