SELECT  ano
       ,mes
       ,CASE WHEN
    COALESCE(categoria,666) = 666 THEN maxcat ELSE categoria END cat

 FROM (

SELECT ano
      ,mes
      ,maxcat
      ,COALESCE(cat,0) as cat,
      CASE WHEN
         Extract('Year' From Now()) >= ano AND  Extract('Month' From Now()) > mes AND COALESCE(cat,0) = 0
      THEN 0
      ELSE cat END as categoria

      FROM (


SELECT

     CAST(EXTRACT(YEAR FROM G)   AS INTEGER ) AS ano
    ,CAST(EXTRACT(MONTH FROM G) AS INTEGER) AS mes
    ,F.categoria AS maxcat
    ,F.ano AS fim_ano
    ,F.mes AS fim_mes
    ,CASE
    WHEN CAST(EXTRACT(YEAR FROM G) AS INTEGER ) < 2017 AND COALESCE(T.categoria,0) <= 0 THEN 0
        WHEN CAST(EXTRACT(YEAR FROM G) AS INTEGER ) >= 2019 AND  CAST(EXTRACT(MONTH FROM G) AS INTEGER) = T.mes     AND     COALESCE(T.categoria,0) = 0 THEN F.categoria
    ELSE T.categoria END AS cat

FROM generate_series(DATE'2016-01-01',DATE'2022-01-01',INTERVAL '1 month') G


    LEFT JOIN(
            SELECT ano
                ,mes
                ,COALESCE(id_categoria,0) AS categoria

            FROM cadastros.oficinas_elegiveis
                WHERE id_oficina = 1691

         ) T ON 1=1 AND T.ano = CAST(EXTRACT(YEAR FROM G) AS INTEGER)  AND T.mes = CAST(EXTRACT(MONTH FROM G) AS INTEGER)


    LEFT JOIN(
            SELECT max(id) as id, ano, mes,
                id_categoria AS categoria
             FROM cadastros.oficinas_elegiveis
            WHERE id_oficina = 1691
            GROUP BY id,ano,mes,id_categoria
            ORDER BY id DESC
            LIMIT 1
         ) F ON 1=1



WHERE 1=1
GROUP BY 1,2,3,4,5,6
ORDER BY CAST(EXTRACT(YEAR FROM G)  AS INTEGER )
) FOO
WHERE 1=1
order by ano,mes
) AM