Faire apparaitre la colonne dans mon tableau même si sum(montant) est null

SELECT IFNULL(SUM(montant_cdv),0) AS total
       ,seq AS mois 
FROM 
  (
        SELECT 1 AS seq 
        UNION SELECT 2  AS seq 
        UNION SELECT 3  AS seq 
        UNION SELECT 4  AS seq 
        UNION SELECT 5  AS seq 
        UNION SELECT 6  AS seq 
        UNION SELECT 7  AS seq 
        UNION SELECT 8  AS seq 
        UNION SELECT 9  AS seq 
        UNION SELECT 10 AS seq 
        UNION SELECT 11 AS seq 
        UNION SELECT 12 AS seq 
  ) AS SEQ 
 LEFT JOIN cdv C ON SEQ.seq = MONTH(C.date_cdv)
 GROUP BY seq
ORDER BY seq ASC

SELECT SAQ.seq
      ,T.total
FROM 
  (
    SELECT 1 AS seq 
    UNION SELECT 2  AS seq 
    UNION SELECT 3  AS seq 
    UNION SELECT 4  AS seq 
    UNION SELECT 5  AS seq 
    UNION SELECT 6  AS seq 
    UNION SELECT 7  AS seq 
    UNION SELECT 8  AS seq 
    UNION SELECT 9  AS seq 
    UNION SELECT 10 AS seq 
    UNION SELECT 11 AS seq 
    UNION SELECT 12 AS seq 
  ) AS SEQ 
LEFT JOIN (
   SELECT IFNULL(SUM(montant_cdv),0) AS total, MONTH(C.date_cdv) AS mois 
   FROM cdv C 
     LEFT JOIN `rcaisse` ON `rcaisse`.`id` = C.`id_caisse`
     LEFT JOIN `rcomptable` ON `rcomptable`.`id` = `rcaisse`.`id_rcompt`
     LEFT JOIN `gt_rcomptable` ON `gt_rcomptable`.`id_rcomptable` = `rcomptable`.`id`
     LEFT JOIN `rcaisse_tab_cdv` ON `rcaisse_tab_cdv`.`rcompt` = `rcomptable`.`id`
    WHERE type_cdv = :cdv
    AND nom = :secteur
    AND entite_cdv = :entite
    GROUP BY MONTH(C.date_cdv)
) T ON SEQ.seq = T.mois

 ORDER BY seq ASC

SELECT IFNULL(SUM(montant_cdv),0) AS total
       ,MONTH(date_cdv) AS mois 
FROM 
  (
        SELECT 1 AS seq 
        UNION SELECT 2  AS seq 
        UNION SELECT 3  AS seq 
        UNION SELECT 4  AS seq 
        UNION SELECT 5  AS seq 
        UNION SELECT 6  AS seq 
        UNION SELECT 7  AS seq 
        UNION SELECT 8  AS seq 
        UNION SELECT 9  AS seq 
        UNION SELECT 10 AS seq 
        UNION SELECT 11 AS seq 
        UNION SELECT 12 AS seq 
  ) AS SEQ 
 LEFT JOIN cdv C ON SEQ.seq = MONTH(C.date_cdv)
 LEFT JOIN `rcaisse` ON `rcaisse`.`id` = C.`id_caisse`
 LEFT JOIN `rcomptable` ON `rcomptable`.`id` = `rcaisse`.`id_rcompt`
 LEFT JOIN `gt_rcomptable` ON `gt_rcomptable`.`id_rcomptable` = `rcomptable`.`id`
 LEFT JOIN `rcaisse_tab_cdv` ON `rcaisse_tab_cdv`.`rcompt` = `rcomptable`.`id`
WHERE type = :cdv
  AND nom = :secteur
  AND entite_cdv = :entite
GROUP BY MONTH(C.date_cdv)
ORDER BY MONTH(C.date_cdv) ASC

CREATE TABLE `cdv` (
  `id_cdv` int(11) NOT NULL,
  `type_cdv` int(11) NOT NULL,
  `date_cdv` date NOT NULL,
  `montant_cdv` decimal(20,2) NOT NULL,
  `id_caisse` int(11) NOT NULL,
  `entite_cdv` int(11) NOT NULL
)

// Boucle des montants
			$gt ="";
			foreach ($nbr as $totalgt) {
				$gt .= "<td>".$totalgt['total']."</td>";
			
			}
			return $gt;