Mysql using SUM and DISTINCT - Why not use GROUP

Mysql using SUM and DISTINCT  - Why not use GROUP

Yes the answers in the title .  Consider

SELECT SUM(DISTINCT te.field_company_total_employees_value)

    FROM field_data_field_company_total_employees AS te

    INNER JOIN  field_data_field_user_company AS uc ON te.entity_id = uc.field_user_company_target_id

    INNER JOIN field_claiming_user AS cu ON uc.entity_id = cu.field_claiming_user_target_id

    INNER JOIN field_data_field_urn_offer as uo ON cu.entity_id = uo.entity_id

    WHERE uo.field_urn_offer_target_id = 20

GROUP BY te.id

Produced the results wanted.