本文介绍了如何使用 MySQL 计算移动平均值?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我需要做类似的事情:
SELECT value_column1
FROM table1
WHERE datetime_column1 >= '2009-01-01 00:00:00'
ORDER BY datetime_column1;
除了value_column1，我还需要检索一个移动平均线<value_column1 的前 20 个值的/a>.
Except in addition to value_column1, I also need to retrieve a moving average of the previous 20 values of value_column1.
首选标准 SQL，但如有必要，我将使用 MySQL 扩展.
Standard SQL is preferred, but I will use MySQL extensions if necessary.
推荐答案
这只是我的头顶，我正在出门的路上，所以它未经测试.我也无法想象它会在任何类型的大数据集上表现得很好.我确实确认它至少运行没有错误.:)
This is just off the top of my head, and I'm on the way out the door, so it's untested. I also can't imagine that it would perform very well on any kind of large data set. I did confirm that it at least runs without an error though. :)
SELECT
value_column1,
(
SELECT
AVG(value_column1) AS moving_average
FROM
Table1 T2
WHERE
(
SELECT
COUNT(*)
FROM
Table1 T3
WHERE
date_column1 BETWEEN T2.date_column1 AND T1.date_column1
) BETWEEN 1 AND 20
)
FROM
Table1 T1
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