Requette sql avec variable de plusieur données

$tchat=$bdd->prepare('SELECT DISTINCT id_unique FROM tchat_prive WHERE id_client_destinataire = ? ');
		$tchat->execute(array($getid));
			while($resulta_tchat = $tchat->fetch())
			{
				$valid_id=$resulta_tchat['id_unique'];
				$compt_cle=$bdd->prepare('SELECT * FROM tchat_prive WHERE id_unique = ? ');
				$compt_cle->execute(array($valid_id));
				while($affiche_cle = $comtp_cle->fetch())
				{			
					$id_ex = $affiche_cle['id_client_expediteur'];
					$tchat_actif=$bdd->prepare('SELECT * FROM membre WHERE id = ?  ORDER BY ID DESC LIMIT 0, 50');
					$tchat_actif->execute(array($id_ex));
					while($donnees = $tchat_actif->fetch())
					{