问题描述
大多数数据库都具有用于计算中位数的内置函数，但在Amazon Redshift中我看不到中位数.
Most databases have a built in function for calculating the median but I don't see anything for median in Amazon Redshift.
您可以使用nth_value()和count()分析函数的组合来计算中位数，但这看起来有些古怪.如果分析数据库没有用于计算中位数的内置方法，我会感到非常惊讶，所以我假设我错过了一些东西.
You could calculate the median using a combination of the nth_value() and count() analytic functions but that seems janky. I would be very surprised if an analytics db didn't have a built in method for computing median so I'm assuming I'm missing something.
http://docs.aws.amazon.com/redshift/latest/dg/r_Examples_of_NTH_WF .html http://docs.aws.amazon.com/redshift/latest/dg/c_Window_functions.html
推荐答案
从2014年10月17日起，Redshift支持 MEDIAN 窗口函数:
And as of 2014-10-17, Redshift supports the MEDIAN window function:
# select min(median) from (select median(num) over () from temp);
min
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4.0
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