Question

I have a text[] ARRAY column within a PostgreSQL table and I need to run char_length() on each element inside the array within a SELECT query (normal SQL, not plpgsql) so that if any of the elements is more than 25 characters long, the SELECT returns ‘t’ and ‘f’ otherwise. I know I can loop over the text[] within a custom plpgsql function but due to other reasons I need to find a way to do this in SQL directly.

Is it possible?

Answer 1

As of PostgreSQL 8.4, you can use the UNNEST function:

SELECT MAX((char_length(string) > 25)::INT)::BOOLEAN
FROM (
    SELECT my_array,UNNEST(my_array) AS string
    FROM my_table
) AS x
GROUP BY my_array;