SELECT
    DATE_FORMAT(month, 'YYYY-MM') AS month,
    region,
    SUM(unique_devices) AS unique_devices
FROM
(
        SELECT
      CONCAT(year,'-',LPAD(month,2,'0'),'-01') AS month,
      cr.wmf_region AS region,
      uniques_estimate as unique_devices
    FROM 
        wmf.unique_devices_per_project_family_monthly ud
    LEFT JOIN gdi.country_meta_data cr 
    ON ud.country_code=cr.country_code_iso_2
    WHERE 
        year >= 2018
      AND project_family = 'wikipedia'
) a

GROUP BY DATE_FORMAT(month, 'YYYY-MM') , region

LIMIT 1000