结果中的新SQL PDO查询

Question

I'm very new to PDO SQL queries. I have the following code which works well. When the result returns only 1 row, I then want to set that row to valid = FALSE" . How do I do that?

$sql = "SELECT * FROM `passcodes` WHERE `passcode` = '$passcode' AND `valid` = TRUE";
$stmt = $DBcon->prepare($sql);
$stmt->execute();
$count = $stmt->rowCount();
if($count == 1) {
    //do this
} else {
    //do that
}

Answer 1

Yet another solution.

IF you interested in "else" section mentioned above, you can combine elegant solution from @YourCommonSense with checking how much rows was changed in UPDATE. MySQL returns such info!

$sql = "UPDATE `passcodes` SET `valid` = FALSE WHERE `passcode` = ? AND `valid` = TRUE";
$DBcon->prepare($sql)->execute([$passcode]);
if ($stmt->rowCount() == 0) {
  // do this when nothing found
}

Answer 2

I then want to set that row to valid = FALSE". How do I do that?

this is what SQL is for.

$sql = "UPDATE `passcodes` SET `valid` = FALSE WHERE `passcode` = ? AND `valid` = TRUE";
$DBcon->prepare($sql)->execute([$passcode]);

this is all the code you need.

Answer 3

This will work with count of result rows equal or greater than 1. I recommend to use placeholders for prepared statements:

$sql = "SELECT `id` FROM `passcodes` WHERE `passcode` = ? AND `valid` = TRUE";
$stmt = $DBcon->prepare($sql);
$stmt->execute([ $passcode ]);
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
if($rows) {
    //do this
    $sql = "UPDATE `passcodes` SET `valid` = FALSE WHERE `id` = ?";
    $stmt = $DBcon->prepare($sql);
    foreach ($rows as $r) {
        $stmt->execute([ $r['id'] ]);
    }
} else {
    //do that
}