BigQuery 运行总计

Question

我在 BigQuery 中无法使用运行总计。

我找到了一个适用于此处的示例： BigQuery SQL running totals

SELECT word, word_count, SUM(word_count) OVER(ORDER BY word DESC)
FROM [publicdata:samples.shakespeare]
WHERE corpus  = 'hamlet'
AND word > 'a' LIMIT 30

但我真正想做的是计算占总数 80% 的最流行词的数量 word_count。所以我试着计算运行总数，同时先按 word_count 订购：

SELECT word, word_count, SUM(word_count) OVER(ORDER BY word_count DESC)
FROM [publicdata:samples.shakespeare]
WHERE corpus  = 'hamlet'
AND word > 'a' LIMIT 30

但我明白了：

Row word    word_count  f0_  
1   o'er    18          18   
2   answer  13          31   
3   meet    8           39   
4   told    5           44   
5   treason 4           **52**   
6   quality 4           **52**   
7   brave   3           55

第 5 行到第 6 行的运行总数没有增加。可能是因为在这两种情况下 word_count 都是 4。

我做错了什么？

也许有更好的方法？我的计划是计算运行总数。然后将其除以 sum(word_count) OVER() 并仅过滤小于 80% 的行。然后计算这些行的数量。

Answer 1

首先，删除 "LIMIT 30" - 它会干扰 OVER() 子句。

你想要比例？试试 RATIO_TO_REPORT:

SELECT word, word_count, RATIO_TO_REPORT(word_count) OVER(ORDER BY word_count DESC)
FROM [publicdata:samples.shakespeare]
WHERE corpus  = 'hamlet'
AND word > 'a'

您是否希望具有相同值的连续行增加？确定这些行的顺序，次要顺序：

SELECT word, word_count, RATIO_TO_REPORT(word_count) OVER(ORDER BY word_count DESC, word)
FROM [publicdata:samples.shakespeare]
WHERE corpus  = 'hamlet'
AND word > 'a'

你想要覆盖80%的最热门词吗？把这些比率加起来，然后过滤掉剩下的：

SELECT word, word_count, sum_ratio
FROM (
 SELECT word, word_count, SUM(ratio) OVER(ORDER BY ratio, word) sum_ratio
 FROM (
    SELECT word, word_count, RATIO_TO_REPORT(word_count) OVER(ORDER BY word_count DESC, word) ratio
    FROM [publicdata:samples.shakespeare]
    WHERE corpus  = 'hamlet'
    AND word > 'a' 
 )
)
WHERE sum_ratio>0.8

Row word    word_count  sum_ratio    
1   is      313         0.8125175752219499   
2   it      361         0.827019644076648    
3   in      400         0.8430884184308841   
4   my      441         0.8608042421564295   
5   you     499         0.8808500381633391   
6   of      630         0.906158357771261    
7   to      635         0.9316675370586108   
8   and     706         0.9600289237938375   
9   the     995         0.9999999999999999

BigQuery 运行总计

BigQuery running totals

cumulative-sum

window-functions

google-bigquery

BigQuery 运行 总计

BigQuery running totals

cumulative-sum

window-functions

google-bigquery

BigQuery 运行总计