Mysql 计算每个帐户组的记录数量，其中加入日期=每月

我有一个表accounts，其中包含accountgroup和joineddate以及其他字段。使用MySQL版本5.5.35-cll

基本上，我想做的是计算每个账户组每月发生的“注册”数量。不仅仅是每月的总金额，还需要知道每个accountgroup每月有多少注册

所以结果会是这样的：

我尝试了几种不同的方法，但只成功地获得了一个月的需求，而不是一年中所有的月份。当我尝试使用SUM时，它看起来像是在工作，但它并没有像预期的那样工作-似乎它认为每个组每月最多有1次注册，而实际上有些组至少有4或5次注册

这是我最近一次尝试SUM失败：

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");

有人能告诉我怎么做吗？我很困惑：

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提前感谢您的帮助

你们非常接近。您需要将年份条件放入if中。例如：

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

你不需要最后的括号。因此，查询应该如下所示：

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";

另外，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，不需要转义这些名称。使用双引号或反勾号。仅对字符串和日期常量使用单引号