sql n日均线-mysql presto

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于 2021-10-22 17:21:26 发布

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文章标签： sql mysql 数据库

本文链接：https://blog.youkuaiyun.com/mnbwz/article/details/120910071

本文通过SQL查询展示了如何利用窗口函数计算指定日期范围内（前2天加上当天）的数值总和与平均值，例如3日均线。示例中使用了`SUM()`和`AVG()`函数结合`ROWS BETWEEN`子句来实现这一功能。

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with day_num as (
    select '2021-01-01' fd_day, 1 num
    union all select '2021-01-02', 2
    union all select '2021-01-03', 3
    union all select '2021-01-04', 4
    union all select '2021-01-05', 5
)
select fd_day, num, sum(num) over(
    order by fd_day
    --前2条、本条、后0条记录的和
    rows between 2 preceding and 0 following
) as sum_num, avg(num) over(
    order by fd_day
    --前2条、本条、后0条记录的均值，即3日均线
    rows between 2 preceding and 0 following
) as avg_num
from day_num