将 BigQuery javascript UDF 应用于组

Question

我正在尝试将 javascript 用户定义的函数应用于组。在下面的代码中，--group by my_group within tuple 被注释掉了。我想在 test_data 内的每个 my_group 上应用临时函数 test。如果 group by 被注释掉，代码就会运行。如果我尝试包含分组依据，它会生成一个“标量子查询生成多个元素”。我应该做些什么更改才能按组输出一个数组 (my_group)？

#standardSQL create function
CREATE TEMP FUNCTION test(a ARRAY<STRING>) 
RETURNS ARRAY< STRING >
LANGUAGE js AS '''
  var combine = function(a) {
    var fn = function(n, src, got, all) {
      if (n == 0) {
        if (got.length > 0) {
          all[all.length] = got;
        } return;
      }
      for (var j = 0; j < src.length; j++) {
        fn(n - 1, src.slice(j + 1), got.concat([src[j]]), all);
      } return;
    }
    var all = [];
    for (var i = 1; i < a.length; i++) {
      fn(i, a, [], all);
    }
    all.push(a);
    return all;
  } 
  return combine(a)
''';

 WITH test_data AS (
  SELECT  'Shirt' item, 'Cashless' my_group UNION ALL
  SELECT  'Jeans', 'Cashless' UNION ALL
  SELECT  'Jeans', 'Cash' UNION ALL
  SELECT  'Cap', 'Cash' UNION ALL
  SELECT  'Shirt', 'Cash' UNION ALL
  SELECT  'Cap', 'Cashless'

),

tuple as (  
  SELECT ARRAY_AGG(DISTINCT item) items
  FROM test_data

  --group by my_group (uncommenting it creates error)
)

select * from unnest(test((select items from tuple)))

我正在寻找如下输出：

my_group    Item
Cash        Shirt
Cash        Jeans
Cash        Cap
Cash        Shirt,Jeans
Cash        Shirt,Cap
Cash        Jeans,Cap
Cash        Shirt,Jeans,Cap
Cashless    Shirt
Cashless    Jeans
Cashless    Cap
Cashless    Shirt,Jeans
Cashless    Shirt,Cap
Cashless    Jeans,Cap
Cashless    Shirt,Jeans,Cap

Answer 1

考虑以下内容（省略功能部分以使答案足够紧凑...）

 WITH test_data AS (
  SELECT  'Shirt' item, 'Cashless' my_group UNION ALL
  SELECT  'Jeans', 'Cashless' UNION ALL
  SELECT  'Jeans', 'Cash' UNION ALL
  SELECT  'Cap', 'Cash' UNION ALL
  SELECT  'Shirt', 'Cash' UNION ALL
  SELECT  'Cap', 'Cashless'
), tuple as (  
  SELECT my_group, ARRAY_AGG(DISTINCT item) items
  FROM test_data
  group by my_group 
)
select my_group, item
from tuple,
unnest(test(items)) item

有输出

将 BigQuery javascript UDF 应用于组

Applying BigQuery javascript UDF to groups

google-bigquery

bigquery-udf