MySQL计数包括不在日期范围内的月份

Question

假设我有一个包含以下表的表：

+----+-----------+---------+-------------------------+
| id |  item     |  ....   | dateLogged              |
+----+-----------+---------+-------------------------+
|  1 | 2015-001  |  ....   | 2015-06-01 12:09:00     |
|  2 | 2015-001  |  ....   | 2015-06-01 12:09:00     |
|  3 | 2015-002  |  ....   | 2015-06-30 15:40:02     |
|  4 | 2015-002  |  ....   | 2015-06-30 15:40:03     |
|  5 | 2015-003  |  ....   | 2015-07-02 13:38:22     |
+----+-----------+---------+-------------------------+

我想根据年份，月份从dateLogged中搜索项目数，并使用预期数据：

+--------+----------+----------------+
| year   |  month   |     total      | 
+--------+----------+----------------+
|  2015  | January  |      0         | 
|  2015  | February |      0         | 
|  2015  | March    |      0         | 
|  2015  | April    |      0         | 
|  2015  | May      |      0         | 
|  2015  | June     |      4         | 
|  2015  | July     |      1         | 
|  2015  | August   |      0         | 
|  2015  | September|      0         | 
|  2015  | October  |      0         | 
|  2015  | November |      0         | 
|  2015  | December |      0         |
+--------+----------+----------------+

但是我只能基于以下SQL来获取它：

SELECT DATE_FORMAT(dateLogged, '%Y') as 'year', MONTHNAME(dateLogged) 
as 'month', COUNT(id) as 'total' from item a where dateLogged >= '2015-06-29 00:00:00' 
and dateLogged <= '2015-07-02 23:59:59' 
GROUP BY DATE_FORMAT(a.dateLogged, '%Y%m');

+--------+---------+----------------+
| year   |  month  |  No of items   | 
+--------+---------+----------------+
|  2015  | June    |      4         | 
|  2015  | July    |      1         | 
+----+-------------+----------------+    

我曾尝试从stackoverflow的其他位置进行搜索，但无法获得任何答案，或者可能错过了。 想知道是否有任何解决方案，谢谢。

我正在使用Java进行计算，因此也欢迎使用Java进行上述计算的任何建议。

Answer 1

您也可以使用循环迭代数月和数年然后查找计数，来更改查询以返回0值。 像这样：

Map<String, Integer> values = new HashMap<String, Integer>();
for(int year = 2015; year < 2017; year++)
{
    for(int month = 1; month <= 12; month++)
    {
        rs = stmt.executeQuery("SELECT COUNT(id) as 'total' from item where
                 MONTH(dateLogged) = " + month + " and YEAR(dateLogged) = " + year + ";";
        rs.next();
        int count = rs.getInt("total");
        String time = Integer.toString(year) + "-" + Integer.toString(month);
        values.Add(time, count);
    }
}

这将为您返回如下地图：

values['2015-1'] = 0;
values['2015-2'] = 0; 

.. 等等。

当然，您可以根据需要将返回的计数与年和月一起存储，具体取决于您希望如何进一步使用它。

Answer 2

一个想法是以某种方式创建日历表并使用它，以便您在2015年的每个月都有一行：

SELECT DATE_FORMAT(m, '%Y') as 'year', 
       MONTHNAME(m) as 'month',
       COUNT(id) as 'total' 
FROM (SELECT '2015-01-01' AS m UNION ALL SELECT '2015-02-01' UNION ALL
      SELECT '2015-03-01' UNION ALL SELECT '2015-04-01' UNION ALL 
      SELECT '2015-05-01' UNION ALL SELECT '2015-06-01' UNION ALL 
      SELECT '2015-07-01' UNION ALL SELECT '2015-01-08' UNION ALL 
      SELECT '2015-09-01' UNION ALL SELECT '2015-10-01' UNION ALL 
      SELECT '2015-11-01' UNION ALL SELECT '2015-12-01') AS x
LEFT JOIN item a 
ON DATE_FORMAT(a.dateLogged, '%Y%m') = DATE_FORMAT(x.m, '%Y%m') 
   AND dateLogged >= '2015-06-29 00:00:00' 
   AND dateLogged <= '2015-07-02 23:59:59' 
GROUP BY DATE_FORMAT(x.m, '%Y%m');

上面的查询利用排序此表用作一个基础，2015年的在线日历表的FROM子句，因此该查询返回每个 2015年的几个月内排。

在这里演示