您可以尝试吗?

select count(*), DATE_FORMAT(timestamp, "%Y-%m-01")
from title
group by DATE_FORMAT(timestamp, "%Y-%m-01")

请注意，MONTH()不能如下区分"2013-01-01"和"2014-01-01".

Please, note that MONTH() can't differentiate '2013-01-01' and '2014-01-01' as follows.

mysql> SELECT MONTH('2013-01-01'), MONTH('2014-01-01');
+---------------------+---------------------+
| MONTH('2013-01-01') | MONTH('2014-01-01') |
+---------------------+---------------------+
|                   1 |                   1 |
+---------------------+---------------------+