Php sql , calcule

Bonjour ,

 $bdd=new PDO('mysql:host=localhost;dbname=bppro;charset=UTF8','root','');



       // la 1ere requête , retourne la 1ere somme ( les entres comptable de la caisse ) 
       $reponse=$bdd->query(' (select sum(total) as sumt from
       ( select ROUND(sum(montant),3) as total from opp where  nom_opp="ver" and date=(select date_format(now(),"%Y-%m-%d") )
       UNION
        select ROUND(sum(montant),3) as total from opp where  nom_opp="vdv" and date=(select date_format(now(),"%Y-%m-%d") )
        UNION
         select ROUND(sum(montant),3) as total from opp where  nom_opp="caie" and date=(select date_format(now(),"%Y-%m-%d") )

       ) t1 '); 



          //la 2eme requête , retourne la 2eme somme ( les sorties comptable de la caisse ) 

      $reponse1=$bdd->query(' (select sum(total) as sumt1 from
       ( select ROUND(sum(montant),3) as total from opp where  nom_opp="adv" and date=(select date_format(now(),"%Y-%m-%d") )
       UNION
        select ROUND(sum(montant),3) as total from opp where  nom_opp="csh" and date=(select date_format(now(),"%Y-%m-%d") )
        UNION
         select ROUND(sum(montant),3) as total from opp where  nom_opp="caid" and date=(select date_format(now(),"%Y-%m-%d") )

       ) t2 ');




          //la 3eme requête , retourne le solde veille 
       
        $reponse2=$bdd->query('select montant from opp where nom_opp="veille " and date=(select date_format(now(),"%Y-%m-%d")');


 while($donnees1=$reponse->fetch()&& $donnees2=$reponse1->fetch() && $donnees3=$reponse2->fetch() ){

$a= ($donnees['sumt']+$donnees['sumt2']) - $donnees3['montant'];
echo("$a");

}

........................................................................................................

quand j’exécute les 2 le premier requêtes sql en wamp , m'a donnes les résultats corrects , mais dans la page php il m'affiche ce msg

Fatal error: Call to a member function fetch() on a non-object .

merci de votre aide .



EDIT : AJOUT DES BALISES DE CODE