MySQL查询每月获取计数

Question

我有一个供用户使用的表，该表具有一个名为“ created”的字段，该字段具有注册日期。

如何获得包含过去12个月每月注册数量计数的列表？像这样：

Month   Count
1        1232
2        2222
3         122
4        4653
...       ...
12       7654

我不习惯使用mysql，所以直到现在，我只知道如何计算去年的注册数量，而不是如何按最近12个月的数量进行分组。提前致谢！

更新

现在，我使用@fthiella解决方案来得到这个：

+------------------------------+-------------------------------+----------+
| Year(FROM_UNIXTIME(created)) | Month(FROM_UNIXTIME(created)) | Count(*) |
+------------------------------+-------------------------------+----------+
|                         2012 |                             4 |     9927 |
|                         2012 |                             5 |     5595 |
|                         2012 |                             6 |     4431 |
|                         2012 |                             7 |     3299 |
|                         2012 |                             8 |      429 |
|                         2012 |                            10 |     3698 |
|                         2012 |                            11 |     6208 |
|                         2012 |                            12 |     5142 |
|                         2013 |                             1 |     1196 |
|                         2013 |                             2 |       10 |
+------------------------------+-------------------------------+----------+

我如何强制查询给我计数为0的月份？

@fthiella解决方案（非常感谢！）：

     SELECT y, m, Count(users.created)
     FROM (
      SELECT y, m
      FROM
         (SELECT YEAR(CURDATE()) y UNION ALL SELECT YEAR(CURDATE())-1) years,
         (SELECT 1 m UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4
           UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8
           UNION ALL SELECT 9 UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12) months) ym
       LEFT JOIN users
       ON ym.y = YEAR(FROM_UNIXTIME(users.created))
          AND ym.m = MONTH(FROM_UNIXTIME(users.created))
     WHERE
       (y=YEAR(CURDATE()) AND m<=MONTH(CURDATE()))
       OR
       (y<YEAR(CURDATE()) AND m>MONTH(CURDATE()))
     GROUP BY y, m;

结果：

+------+----+----------------------+
| y    | m  | Count(users.created) |
+------+----+----------------------+
| 2012 |  5 |                 5595 |
| 2012 |  6 |                 4431 |
| 2012 |  7 |                 3299 |
| 2012 |  8 |                  429 |
| 2012 |  9 |                    0 |
| 2012 | 10 |                 3698 |
| 2012 | 11 |                 6208 |
| 2012 | 12 |                 5142 |
| 2013 |  1 |                 1196 |
| 2013 |  2 |                   10 |
| 2013 |  3 |                    0 |
| 2013 |  4 |                    0 |
+------+----+----------------------+

Answer 1

如果创建的是INT字段，则应使用FROM_UNIXTIME函数将其转换为日期字段，然后使用MONTH函数提取月份：

SELECT Month(FROM_UNIXTIME(created)), Count(*)
FROM yourtable
WHERE FROM_UNIXTIME(created) >= CURDATE() - INTERVAL 1 YEAR
GROUP BY Month(FROM_UNIXTIME(created))

这将计算最近12个月中创建的所有行。请注意，最好按年份分组：

SELECT Year(FROM_UNIXTIME(created)), Month(FROM_UNIXTIME(created)), Count(*)
FROM yourtable
WHERE FROM_UNIXTIME(created) >= CURDATE() - INTERVAL 1 YEAR
GROUP BY Year(FROM_UNIXTIME(created)), Month(FROM_UNIXTIME(created))

如果您需要计算注册号而不是行数，则可以使用类似

COUNT(registration_number)

跳过空值，或

COUNT(DISTINCT registration_number)

仅计算不同的。

编辑

如果您还需要显示count = 0的月份，我将使用类似这样的查询，该查询返回当前年份和上一年的所有月份：

SELECT y, m
FROM
  (SELECT YEAR(CURDATE()) y UNION ALL SELECT YEAR(CURDATE())-1) years,
  (SELECT 1 m UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4
    UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8
    UNION ALL SELECT 9 UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12) months;

然后，我将使用LEFT JOIN，它返回第一个查询的所有行，并且仅返回匹配的第二个查询的行：

SELECT y, m, Count(yourtable.created)
FROM (
  SELECT y, m
  FROM
    (SELECT YEAR(CURDATE()) y UNION ALL SELECT YEAR(CURDATE())-1) years,
    (SELECT 1 m UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4
      UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8
      UNION ALL SELECT 9 UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12) months) ym
  LEFT JOIN yourtable
  ON ym.y = YEAR(FROM_UNIXTIME(yourtable.created))
     AND ym.m = MONTH(FROM_UNIXTIME(yourtable.created))
WHERE
  (y=YEAR(CURDATE()) AND m<=MONTH(CURDATE()))
  OR
  (y<YEAR(CURDATE()) AND m>MONTH(CURDATE()))
GROUP BY y, m

（请注意，这里我只是考虑最近的12个月，因此，如果我们处于2013年4月中旬，它将计算2012年5月至4月13日之间的行数，如果这不是正确的行为，请告诉我）