我如何将字符串字段取消嵌套到 SQL BIGQUERY 中的行中

Question

how to unnest a string field Table Flags: id of type integer and categories of type string

ID	Categories
1201	Uncategorized, Issues from Project Side, CI Configurations Issue
1202	Machine Stability, Machine Stability, Machine Stability,

Output needed

ID	categories
1201	Uncategorized
1201	Issues from project side
1201	CI Configurations Issue
1202	Machine Stability
1202	Machine Stability
1202	Machine Stability

Thanks

 select *,
  (select ( categories)
    from unnest(split(categories)) categories
 )as  distinct_product_count
   

 FROM `Flags` 

i got error Scalar subquery produced more than one element

Answer 1

You don't need to use a subquery to do this, you are right to use split within the unnest function but you can specify it right after the from clause like this:

select 
  ID,
  category
from `Flags`, unnest(split(categories)) as category