如何使用数据计数按月和年分组？

Question

我有一张桌子上有这样的数据：

id | question | pub_date
1  | qeustion1| 2012-12-03
2  | qeustion2| 2012-12-06 
3  | qeustion3| 2012-11-03 
4  | qeustion4| 2011-12-03

我想要一个输出，比如:它应该根据年份、月份结果计数和Desc顺序来计数记录，并且还应该显示每一行数据。

就我而言：

• 年份:2012年有3项记录
• 月份:2012年12月份有2次记录
• 年份:2011年有1次记录
• 月份:2011年有12个月创1次记录。

我试过这样做：

SELECT
    EXTRACT(MONTH FROM pub_date) as month, 
    EXTRACT(YEAR FROM pub_date) as year, 
    Count(id)
FROM 
    mytable
GROUP BY 
    month,
    year
ORDER BY 
    year DESC, 
    month DESC

我需要显示这样的数据，请参阅博客存档站点的部分

Answer 1

我想你想要的结果是：

2012           3
2012 12        2
2012 11        1
2011           1
2011 11        1

您可以通过在两个聚合查询上使用union来获得这个结果：

select s.*
from ((select year(pub_date) as yr, NULL as month, count(*) as cnt
       from t
       group by year(pub_date)
      ) union all
      (select year(pub_date) as yr, month(pub_date) as mon, count(*) as cnt
       from t
       group by year(pub_date), month(pub_date)
      )
     ) s
order by yr desc,
         (case when mon is null then -1 else mon end)

Answer 2

试试这个：

select count(id)
from mytable
group by year(pub_date), month(pub_date)
order by year(pub_date) desc, month(pub_date) desc

如果您想知道有几个月和几年，请使用：

select year(pub_date) as year, month(pub_date) as month, count(id), *
from mytable
group by year(pub_date), month(pub_date)
order by year(pub_date) desc, month(pub_date) desc

获取月份和年份的数据

select year(pub_date) as year, year_count, month(pub_date) as month, count(rowid) as month_count
from mytable u
, (
select year(pub_date) as year, count(rowid) year_count
from mytable
group by year(pub_date)
) as tab
where tab.year = year(u.pub_date)
group by year(pub_date), month(pub_date)