PostgreSQL Integer in Array is not merge-joinable

I would like to perform a FULL OUTER JOIN ON a condition that is an integer being in an array of integer.

The query would look something like this:

SELECT thing FROM table1 t1
FULL OUTER JOIN table2 t2
ON t1.id = ANY(t2.array_of_ids)

But I get the following error:

FULL JOIN is only supported with merge-joinable or hash-joinable join conditions

Is there a way to make this condition merge-joinable ?

Answer

Hmmm . . . Does it work like this?

SELECT thing
FROM table1 t1 FULL OUTER JOIN
     (table2 t2 CROSS JOIN
      UNNEST(t2.array_of_ids) t2_id
     )
     ON t1.id = t2_id;

The issue with this is that it will multiply the number of rows. So, how about just constructing the FULL JOIN?

SELECT . . .
FROM table1 t1 LEFT JOIN
     (table2 t2 CROSS JOIN
      UNNEST(t2.array_of_ids) t2_id
     )
     ON t1.id = t2_id
UNION ALL
SELECT . . .
FROM table2 t2
WHERE NOT EXISTS (SELECT 1
                  FROM UNNEST(t2.array_of_ids) t2_id JOIN
                       table1 t1
                  ON t2_id = t1.id
                 );