if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
}
if (isset($_POST['jouer'] && count($_POST[n] >5))) {
echo "le nombre de cases à cocher est limité à 5";
}

    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;

if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
}
    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;
$nb=count($_POST['n']);
if($nb <= 5) {
$sql="INSERT INTO JEUX (name, city, pays, continent, n1, n2, n3, n4, n5) VALUES ('$pseudo', '$citoyen', '$residant', '$situation_continent', '{$cases_cochees[0]}','{$cases_cochees[1]}','{$cases_cochees[2]}','{$cases_cochees[3]}','{$cases_cochees[4]}');";
$pdostat = $bdd->prepare($sql);
$pdostat->execute();

if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
}
    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;
$nb=count($_POST['n']);
if($nb <= 5) {

if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
}
    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;
$nb=count($_POST['jouer']);
if($nb<=5) {
bla bla bla...

if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
$n=0;
}
    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;
	  $n++;
if($n<=5){
$sql="INSERT INTO JEUX (name, city, pays, continent, n1, n2, n3, n4, n5) VALUES ('$pseudo', '$citoyen', '$residant', '$situation_continent', '{$cases_cochees[0]}','{$cases_cochees[1]}','{$cases_cochees[2]}','{$cases_cochees[3]}','{$cases_cochees[4]}');";
$pdostat = $bdd->prepare($sql);
$pdostat->execute();
}
}
}

Warning: Undefined array key 1 in /home/clients/78f15c369c0786c4a419608e9e60028........
Warning: Undefined array key 2 in /home/clients/78f15c369c0786c4a419608e9e60028a...............
Warning: Undefined array key 3 in home/clients/78f15c369c0786c4a419608e9e60028a...on line 28
Warning: Undefined array key 4 in home/clients/78f15c369c0786c4a419608e9e60028a on line 28
Warning: Undefined array key 2 in home/clients/78f15c369c0786c4a419608e9e60028on line 28
Warning: Undefined array key 3 in home/clients/78f15c369c0786c4a419608e9e60028..on line 28

etc...

if(isset($_POST['jouer'])){
  if(isset($_POST['n'])){
    $cases_cochees = [];
    foreach( $_POST['n'] as $valeur){
      $cases_cochees[] = $valeur;
    }
    
$sql="INSERT INTO JEUX (name, city, pays, continent, n1, n2, n3, n4, n5) VALUES ('$pseudo', '$citoyen', '$residant', '$situation_continent', '{$cases_cochees[0]}','{$cases_cochees[1]}','{$cases_cochees[2]}','{$cases_cochees[3]}','{$cases_cochees[4]}');";
$pdostat = $bdd->prepare($sql);
$pdostat->execute();

$sql="SELECT COUNT(*) AS nombre_colonnes_identiques FROM JEUX INNER JOIN TIRAGE ON JEUX.n1 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR JEUX.n2 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5) OR JEUX.n3 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR JEUX.n4 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5) OR JEUX.n5 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5) WHERE name='$pseudo' AND lastInsertId()";
$pdostat = $bdd->prepare($sql);
$pdostat->execute();
$row = $pdostat->fetch();
$resu = $row['nombre_colonnes_identiques']; 
echo $resu; 

Fatal error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1370 execute command denied to user 'ub6k8_youe'@'%' for routine 'ub6k8_xxxx.lastInsertId' 

SELECT COUNT(*) AS nombre_colonnes_identiques
FROM JEUX
INNER JOIN TIRAGE ON 
JEUX.n1 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR 
JEUX.n2 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR 
JEUX.n3 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR 
JEUX.n4 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5)
OR 
JEUX.n5 IN (TIRAGE.t1, TIRAGE.t2, TIRAGE.t3, TIRAGE.t4, TIRAGE.t5);

SELECT COUNT(*) AS nombre_colonnes_identiques FROM JEUX
WHERE 
  n1 IN (SELECT t1 FROM TIRAGE)
  OR n2 IN (SELECT t2 FROM TIRAGE)
  OR n3 IN (SELECT t3 FROM TIRAGE)
  OR n4 IN (SELECT t4 FROM TIRAGE)
  OR n5 IN (SELECT t5 FROM TIRAGE);

Cardinality violation: 1241 Operand should contain 1 column(s)

<?php

$jeux = [
    ["n1" => 1, "n2" => 2, "n3" => 3, "n4" => 4, "n5" => 5],
    ["n1" => 2, "n2" => 8, "n3" => 20, "n4" => 25, "n5" => 30],
];

$tirages = [["t1" => 8, "t2" => 20, "t3" => 30, "t4" => 31, "t5" => 40]];

foreach ($tirages as $tirage) {
    foreach ($jeux as $jeu) {
        echo "tirage : " . implode(",", $tirage) . "\n";
        echo "jeu : " . implode(",", $jeu) . "\n";

        $intersect = array_intersect($tirage, $jeu);

        echo "count intersect : " . count($intersect) . "\n";

        if (count($intersect) > 0) {
            echo "intersect : " . implode(",", $intersect) . "\n";
        }

        echo "\n";
    }
}

tirage : 8,20,30,31,40
jeu : 1,2,3,4,5
count intersect : 0

tirage : 8,20,30,31,40
jeu : 2,8,20,25,30
count intersect : 3
intersect : 8,20,30