如果 created 是一个 INT 字段，你应该使用 FROM_UNIXTIME 函数将其转换为日期字段，然后 MONTH 提取月份的函数:

If created is an INT field, you should use FROM_UNIXTIME function to convert it to a date field, and then MONTH function to extract the month:

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

这将计算过去 12 个月内创建的所有行.请注意，***也按年份分组:

this will count all the rows that have been created in the last 12 months. Please notice that it's probably better to also group by the YEAR:

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，您可以使用类似

If you need to count the registration numbers instead of the rows, you could use something like

COUNT(registration_number)

跳过空值，或

COUNT(DISTINCT registration_number)

只计算不同的.

编辑

如果您还需要显示 count=0 的月份，我会使用这样的查询来返回当前和上一年的所有月份:

If you also need to show months that have count=0, I would use a query like this that returns all of the months for the current and for the previous year:

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;

然后我会使用一个LEFT JOIN，它返回第一个查询的所有行，并且只返回匹配的第二个查询的行:

And then I'd use a LEFT JOIN, that returns all of the rows of the first query, and only the rows of the second query that matches:

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，这里我只考虑过去 12 个月，所以如果我们在 2013 年 4 月中旬，它将计算 2012 年 5 月 - 4 月 13 日之间的行数，如果这不是正确的行为，请告诉我)

(please notice that here I am considering just the last 12 months, so if we are in the middle April 2013 it will count rows in the interval May 2012 - April 13, if this is not the correct behaviour please let me know)