BigQuery：将 arrays 与 window 子句连接起来

Question

I am working with data from tables for which dummy data could be:

WITH
  Sequences AS (
    SELECT [0, 1, 3] AS some_numbers UNION ALL
    SELECT [2, 4, 8] UNION ALL
    SELECT [0, 5] UNION ALL
    SELECT [2, 16] UNION ALL
    SELECT [0, 7]
  ),
  SELECT
    some_numbers[ORDINAL(1)] AS grp,
    some_numbers[ORDINAL(2)] AS sub_grp,
    some_numbers
  FROM Sequences

I want to combine the arrays within groups of grp but only till last 1 sub_grp .

I tried small things like:

SELECT
  grp,
  sub_grp,
  ARRAY_CONCAT_AGG(some_numbers) OVER (PARTITION BY grp ORDER BY sub_grp ROWS 1 PRECEDING)
FROM numbers

However this results in error:

Analytic function ARRAY_CONCAT_AGG is not supported.

Any pointer how can I fix this problem?

EDIT Adding the expected output. I am expecting the output to be:

Answer 1

But regardless as I am hit by a hard wall of error; any hint which let me give working example, will be of immense help. I can adapt it to my use case:)

Hope below will unblock your efforts

select * except(arrs, pos), 
  format('%t', (select array_concat_agg(arr) from t.arrs)) grouped_numbers 
from (
  select grp, sub_grp, 
    array_agg(struct(some_numbers as arr)) over win arrs,
    row_number() over(partition by grp order by sub_grp) pos
  from sequences, unnest([struct(some_numbers[ordinal(1)] as grp, some_numbers[ordinal(2)] as sub_grp)])
  window win as (partition by grp order by sub_grp rows between current row and 1 following)
) t 
where mod(pos, 2) = 1

if applied to sample data in your question - output is