使用PDO在Select语句中选择多行

Question

I have two tables, I want to select from the first the ID of Salles for each Responsible (he may have many -> array()) .

so I want to select all the salles this responsible have, and I did this statement (which returns an empty array and I am unsure of why):

$sels = $db->prepare("SELECT salle FROM salleresp  WHERE resp = :resp");
$sels->bindParam(':resp',$rsb['matricule']);
$sels->execute();

$rss = $sels->fetchAll(PDO::FETCH_ASSOC);
$questionmarks = str_repeat("?,", count($rss)-1) . "?"; 

 $selectSalle1 = $db->prepare("SELECT * FROM salle WHERE salleId IN ($questionmarks) ");
 $selectSalle1->execute($rss);
 $showAll=$selectSalle1->fetchAll(PDO::FETCH_ASSOC);

when I do:

print_r($showAll);

it return an empty array:

array()

Any suggestions please?

Answer 1

SELECT * FROM salle WHERE salleId IN (SELECT salle FROM salleresp  WHERE resp = :resp)

or

SELECT * FROM salle left join salleresp on (salle.salleId = salleresp.salle)
WHERE resp = :resp)