¿Quién cerró la encuesta?

Si estás utilizando el Explorador de Datos, puedes intentar con esto (SQL)

SELECT 
    pr.created_at AS "Closed At",
    p.topic_id AS "Topic ID",
    p.post_number AS "Post Number",
    u.username AS "Closed By",
    pr.modifications AS "Modifications"
FROM post_revisions pr
JOIN posts p ON p.id = pr.post_id
JOIN users u ON u.id = pr.user_id
WHERE pr.modifications LIKE '%status=closed%'
ORDER BY pr.created_at DESC