ALTER TABLE brand_questions
    ADD COLUMN IF NOT EXISTS question_text TEXT;

UPDATE brand_questions q
SET question_text = COALESCE(
    (
        SELECT v.question_text
        FROM brand_question_versions v
        WHERE v.id = q.current_version_id
        LIMIT 1
    ),
    (
        SELECT v.question_text
        FROM brand_question_versions v
        WHERE v.question_id = q.id
        ORDER BY v.version_no DESC, v.id DESC
        LIMIT 1
    ),
    ''
)
WHERE q.question_text IS NULL;

ALTER TABLE brand_questions
    ALTER COLUMN question_text SET NOT NULL;

ALTER TABLE brand_questions
    DROP COLUMN IF EXISTS current_version_id;

DROP TABLE IF EXISTS brand_question_versions;
