SQL：使用分区作为求和的条件

Question

我有一个简单的查询：

SELECT
    price_band
    ,device
    ,SUM(requests) as requests
From database.price_band_stats
WHERE
    day = '2016-10-31'
    AND product_id = 6584
    and device IN ('Desktop', 'Android')    
GROUP BY
    price_band
    ,device

返回的表格如下所示：

|price_band | device  | requests
0             Android   149007
0.01          Android   466467
0.05          Android   520661
0.1           Android   487273
0             Desktop   319786
0.01          Desktop   1485894
0.05          Desktop   1693395
0.1           Desktop   1547485

我想调整我的代码以添加一个额外的列。新列将对给定设备的价格范围大于或相等的所有请求求和。例如，如果我们在 Android 上采用价格区间 0.05，我想要价格区间为 0.05 或更高（即 0.05 和 0.1）的所有 Android 请求的总和

所以表格看起来像：

price_band      device     requests    request_above_price_band
0               Android    149007      1623408
0.01            Android    466467      1474401
0.05            Android    520661      1007934
0.1             Android    487273      487273
0               Desktop    319786      5046560
0.01            Desktop    1485894     4726774
0.05            Desktop    1693395     3240880
0.1             Desktop    1547485     1547485

Answer 1

你应该使用window function SUM with ORDER BY DESC and partition：

WITH T AS
( SELECT
    price_band
    ,device
    ,SUM(requests) as requests
 From database.price_band_stats
 WHERE
    day = '2016-10-31'
    AND product_id = 6584
    and device IN ('Desktop', 'Android')    
 GROUP BY
    price_band,device
)
SELECT
 price_band, 
 device, 
 requests,
 SUM(requests) OVER (PARTITION BY device  ORDER BY price_band DESC) 
    as request_above_price_band 
 FROM T
ORDER BY device,price_band

SQLFiddle demo