SQL presto - cross join unnest with ordinality flattening

Question

Why is my query not flattening the data as expected?

I am querying a table where columns contain arrays. My goal is to unnest the items in the arrays to find unique items and turn those into rows.

SELECT
table1.tag_names,
table1.tag_ids, 
rank_position
FROM table1
CROSS JOIN UNNEST (tag_ids, tag_names)
   WITH ORDINALITY as T (tag_ids, tag_names, rank_position)
ORDER BY tag_ids

Results:

tag_names	tag_ids	rank_position
["red", "blue", "green"]	[111, 222, 333]	1
["red", "blue", "yellow"]	[111, 222, 444]	4

Desired Results:

tag_names	tag_ids	rank_position
"red"	111	1
"blue"	222	2
"green"	333	3
"yellow"	444	4

What am I missing?

Updated to use alias, new results below:

tag_names	tag_ids	rank_position
"red"	111	1
"red"	111	10
"red"	111	3
"red"	111	12
"yellow"	444	4

Answer 1

You should use alias introduced for the flattened data in the CROSS JOIN UNNEST in the select:

-- sample data
WITH dataset (tag_names, tag_ids) AS (
    VALUES (array['red', 'blue', 'green'], array[111, 222, 444])
) 

-- query
select T.tag_names,
   T.tag_ids, 
   rank_position
from dataset
CROSS JOIN UNNEST (tag_ids, tag_names)
   WITH ORDINALITY as T (tag_ids, tag_names, rank_position)
ORDER BY tag_ids

Output:

tag_names	tag_ids	rank_position
red	111	1
blue	222	2
green	444	3

UPD

ORDINALITY does not work across multiple rows, one way to achieve desired result is to flatten the arrays, then use group by and row_number :

-- sample data
WITH dataset (tag_names, tag_ids) AS (
    VALUES (array['red', 'blue', 'green'], array[111, 222, 333]),
     (array['red', 'blue', 'yellow'], array[111, 222, 444])
) 

-- query
select *, row_number() over (order by tag_ids) rank_position
from (
        select T.tag_names,
            T.tag_ids
        from dataset
            CROSS JOIN UNNEST (tag_ids, tag_names) AS T (tag_ids, tag_names)
            GROUP BY T.tag_names, T.tag_ids
    )
ORDER BY tag_ids

Output:

tag_names	tag_ids	rank_position
red	111	1
blue	222	2
green	333	3
yellow	444	4