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postgresql percentile_cont为所有百分位数返回相同的值

percentile statistics postgresql sql

Letholdrus · 技术社区 · 7 年前

我试图从一些数据中提取百分位数,但每个百分位数的值是相同的。为什么?

SELECT three_sixty_review_aid, 
percentile_cont(0.95) within group (order by questions_combined asc) as p_95,
percentile_cont(0.75) within group (order by questions_combined asc) as p_75,
percentile_cont(0.5) within group (order by questions_combined asc) as p_50,
percentile_cont(0.25) within group (order by questions_combined asc) as p_25,
percentile_cont(0.1) within group (order by questions_combined asc) as p_10,
percentile_cont(0.05) within group (order by questions_combined asc) as p_05
FROM reviews_threesixty.peer_review_avg_combined_per_review
 group by three_sixty_review_aid

1 回复 | 直到 7 年前

Barbaros Özhan 7 年前

因为,对于由 百分位数 列,如果 分组依据 全部已使用 百分位数 提供的列构成单行 三个审查援助 百分位数 柱:

SELECT  percentile_cont(0.95) within group (order by questions_combined asc) as p_95,
        percentile_cont(0.75) within group (order by questions_combined asc) as p_75,
        percentile_cont(0.5) within group (order by questions_combined asc) as p_50,
        percentile_cont(0.25) within group (order by questions_combined asc) as p_25,
        percentile_cont(0.1) within group (order by questions_combined asc) as p_10,
        percentile_cont(0.05) within group (order by questions_combined asc) as p_05
   FROM reviews_threesixty.peer_review_avg_combined_per_review;

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