Pivot for redshift database

Question

I know this question has been asked before but any of the answers were not able to help me to meet my desired requirements. So asking the question in new thread

In r

Answer 1

If you will typically want to query specific subsets of the categories from the pivot table, a workaround based on the approach linked in the comments might work.

You can populate your "pivot_table" from the original like so:

insert into pivot_table (id, Name, json_cats) (
    select id, Name,
        '{' || listagg(quote_ident(Category) || ':' || count, ',')
               within group (order by Category) || '}' as json_cats
    from to_pivot
    group by id, Name
)

And access specific categories this way:

select id, Name,
    nvl(json_extract_path_text(json_cats, 'Snacks')::int, 0) Snacks,
    nvl(json_extract_path_text(json_cats, 'Beer')::int, 0) Beer
from pivot_table

Using varchar(max) for the JSON column type will give 65535 bytes which should be room for a couple thousand categories.