如何在 BigQuery 表的 450 列中找到值“-32767”？

Question

I have a BigQuery table with 450 columns and millions of rows. As can be expected, the table has columns of all types like datetime, date, integer, numeric and string. I want to know which column contains the value "-32767". Is there a way to accomplish this in BigQuery ?

Answer 1

Consider below

create temp function  extract_keys(input string) returns array<string> language js as """
  return Object.keys(JSON.parse(input));
  """;
create temp function  extract_values(input string) returns array<string> language js as """
  return Object.values(JSON.parse(input));
  """;
select col, count(*) cnt
from your_table t,
unnest([struct(to_json_string(t) as json)]),
unnest(extract_keys(json)) col with offset
join unnest(extract_values(json)) val with offset
using(offset)
where val = '-32767'
group by col    

this will give you output like below

Where col3, col2 are columns that have -32767 value and 4,1 is how many rows involved respectively

How can I modify it and give it a subset of columns where I expect the value can be?

Assuming you want to limit "search" to only col1 and col3 - use below

select col, count(*) cnt
from your_table t,
unnest([struct(to_json_string((select as struct col1, col3 from unnest([t]))) as json)]),
unnest(extract_keys(json)) col with offset
join unnest(extract_values(json)) val with offset
using(offset)
where val = '-32767'
group by col