PDO SELECT和UPDATE循环

Question

I'm really bad with php loops like foreach and while, so I seek help.

I need to loop this code:

$loser = $pdo->prepare("SELECT `user` FROM `contest` WHERE `winner`= '0'");
$loser->execute();

$balance = $pdo->prepare("SELECT `balance` FROM `users` WHERE `login` = '$loser'");
$balance->execute();

$new_balance = $balance + 100;

$back = $pdo->prepare("UPDATE `users` SET `balance`= '$new_balance' WHERE `login`= '$loser'");
$back->execute();

$returned = $pdo->prepare("UPDATE `contest` SET `returned`= '1' WHERE `login`= '$loser'");
$returned->execute();

I tried a couple of things and looked for similar questions around here but I couldn't come up with the solution unfortunately. Can somebody help, please?

Answer 1

Thank you everyone. I found a solution:

$stmt = $pdo->prepare('SELECT * from contest  WHERE winner=0');
$stmt -> execute();
while($row = $stmt->fetch()) {

$result_b = $pdo->prepare("SELECT `balance` FROM `users` WHERE `login` = '$row[user]'");

$result_b->execute();

$balance = $result_b->fetchColumn();

$new_balance = $balance + 100;

$back = $pdo->prepare("UPDATE `users` SET `balance` = '$new_balance' WHERE `login` = '$row[user]'");
$back->execute();

$returned = $pdo->prepare("UPDATE `contest` SET `returned` = '1'");
$returned->execute();
}