mysql - 按周分组的记录数的累计总和

Question

我有以下数据库模式

ID  creation_date
1      2019-06-03
2      2019-06-04
3      2019-06-04
4      2019-06-10
5      2019-06-11

我需要按周找出表组的总大小。我正在寻找的输出类似于

year   week number_of_records
2019    23      3
2019    24      5

我正在编写以下查询，它只提供每周创建的记录数

> select year(creation_date) as year, weekofyear(creation_date) as week,
> count(id) from input group by year, week;

我得到的输出是

year   week number_of_records
2019    23      3
2019    24      2

Answer 1

看看窗口(或分析)函数。 与聚合函数不同，窗口函数保留结果行并促进与它们相关的操作。当在 over 子句中使用 order by 时，根据指定的顺序从第一行到当前行进行窗口化，这正是您所需要的。

select year, week, sum(number_of_records) over (order by year, week)
from (
  select year(creation_date) as year, weekofyear(creation_date) as week,
  count(id) as number_of_records
  from input group by year, week
) your_sql

我猜你还需要重置每年的总和，我把它留给你作为练习(提示:partition 子句)。