SELECT
    l.entity_id AS entity_id_l,
    r.entity_id AS entity_id_r,
    l.name_normalized AS name_l,
    r.name_normalized AS name_r
FROM entities AS l
INNER JOIN entities AS r
    ON LEFT(l.name_normalized, 4) = LEFT(r.name_normalized, 4)
WHERE l.entity_id < r.entity_id