need help with pdo

Hi, my first attempt at pdo, will someone tell me where I went astray?
--------------------------------------------------------------------------
the code:

<?php
$host = '127.0.0.1';
$db  = 'homedb';
$user = 'root';
$pass = '';
$charset = 'utf8mb4';

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$options = [
  PDO::ATTR_ERRMODE  => PDO::ERRMODE_EXCEPTION,
  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
  PDO::ATTR_EMULATE_PREPARES  => false,
];
try {
  $pdo = new PDO($dsn, $user, $pass, $options);
} catch (\PDOException $e) {
  throw new \PDOException($e->getMessage(), (int)$e->getCode());
}
echo "<center>";echo date('m/d/y');echo "</center>";

$tenant=$_POST['tenant'];
$unit=$_POST['unit'];
$amtpaid=$_POST['amtpaid'];
$hudpay=$_POST['hudpay'];
$datepaid=$_POST['datepaid'];

$amtpaid='amtpaid';
$amtdue='amtdue';
$hudpay='hudpay';
$prevbal='prevbal';
$latechg='latechg';
$datepaid='datepaid';

$stmt = $pdo->query('SELECT tenant, unit, amtpaid, amtdue, hudpay, prevbal, latechg, datepaid FROM paytbl');
while ($row = $stmt->fetch())
{
  echo $row['tenant'] . "\n";
}

/* if no pay or part pay, add $35 to latechg field and amount not paid to prevbal field */
if ($amtpaid < $amtdue)
{ $latechg = $latechg + "35.00"; $prevbal = $amtdue - $amtpaid; }

/* if payment = amtdue  */
elseif ($amtpaid == $amtdue)
{ $prevbal = $prevbal - $prevbal;
$latechg = $latechg  - $latechg; }

/* *****************************unexpected ';'*******************************
// if over-payment subtract over-payment from prevbal
else ($amtpaid > $amtdue )
{ $prevbal = $amtpaid  - $amtdue;
$latechg = $latechg  - $latechg; }
****************************************************************************** */
/* Perform a query, check for error */
$sql = "UPDATE paytbl SET amtpaid=?, prevbal=?, latechg=?, datepaid=? WHERE unit=?";
prepared_query($conn, $sql, [$amtpaid, $prevbal, $latechg, $datepaid, $unit]);
// $pdo->prepare($sql)->execute([$name, $id]);
?>

PHP:

-------------------------------------------------------------------------
the result:

PDO::ERRMODE_EXCEPTION, PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, PDO::ATTR_EMULATE_PREPARES =>
false, ]; try { $pdo = new PDO($dsn, $user, $pass, $options); } catch (\PDOException $e)
{ throw new \PDOException($e->getMessage(), (int)$e->getCode()); } echo "
";echo date('m/d/y');echo "
"; $tenant=$_POST['tenant']; $unit=$_POST['unit']; $amtpaid=$_POST['amtpaid'];
$hudpay=$_POST['hudpay']; $datepaid=$_POST['datepaid']; $amtpaid='amtpaid'; $amtdue='amtdue';
$hudpay='hudpay'; $prevbal='prevbal'; $latechg='latechg'; $datepaid='datepaid';
$stmt = $pdo->query('SELECT tenant, unit, amtpaid, amtdue, hudpay, prevbal, latechg, datepaid FROM
paytbl'); while ($row = $stmt->fetch()) { echo $row['tenant'] . "\n"; }
/* if no pay or part pay, add $35 to latechg field and amount not paid to prevbal field */
if ($amtpaid < $amtdue) { $latechg = $latechg + "35.00"; $prevbal = $amtdue - $amtpaid; }
/* if payment = amtdue */
elseif ($amtpaid == $amtdue) { $prevbal = $prevbal - $prevbal; $latechg = $latechg - $latechg; }
/* *****************************unexpected ';'*******************************
// if over-payment subtract over-payment from prevbal else ($amtpaid > $amtdue )
{ $prevbal = $amtpaid - $amtdue; $latechg = $latechg - $latechg; }
****************************************************************************** */
/* Perform a query, check for error */
$sql = "UPDATE paytbl SET amtpaid=?, prevbal=?, latechg=?, datepaid=? WHERE unit=?";
prepared_query($conn, $sql, [$amtpaid, $prevbal, $latechg, $datepaid, $unit]);
// $pdo->prepare($sql)->execute([$name, $id]); ?>

Code (markup):

 

There are several errors in the code according to AI:

1. The line $amtpaid='amtpaid'; and $datepaid='datepaid'; are reassigning the values of variables that were already assigned from the form inputs.
   
   
2. The comment block has an unexpected semicolon in the else statement.
   
   
3. The function prepared_query is not defined, so it will result in a fatal error.
   

Here's the corrected code:
<?php
$host = '127.0.0.1';
$db = 'homedb';
$user = 'root';
$pass = '';
$charset = 'utf8mb4';

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$options = [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
PDO::ATTR_EMULATE_PREPARES => false,
];
try {
$pdo = new PDO($dsn, $user, $pass, $options);
} catch (\PDOException $e) {
throw new \PDOException($e->getMessage(), (int)$e->getCode());
}
echo "<center>" . date('m/d/y') . "</center>";

$tenant=$_POST['tenant'];
$unit=$_POST['unit'];
$amtpaid=$_POST['amtpaid'];
$hudpay=$_POST['hudpay'];
$datepaid=$_POST['datepaid'];

/* if no pay or part pay, add $35 to latechg field and amount not paid to prevbal field */
if ($amtpaid < $amtdue) {
$amtdue = 0; // $amtdue is not defined in the code
$latechg = $latechg + 35.00;
$prevbal = $amtdue - $amtpaid;
}
/* if payment = amtdue */
elseif ($amtpaid == $amtdue) {
$prevbal = 0;
$latechg = 0;
}
/* if over-payment subtract over-payment from prevbal */
else { // removed semicolon from else statement
$prevbal = $amtpaid - $amtdue;
$latechg = 0;
}

/* Perform a query, check for error */
$sql = "UPDATE paytbl SET amtpaid=?, prevbal=?, latechg=?, datepaid=? WHERE unit=?";
$pdo->prepare($sql)->execute([$amtpaid, $prevbal, $latechg, $datepaid, $unit]);
?>

 

thanks for the help,
this is the result:
PDO::ERRMODE_EXCEPTION, PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, PDO::ATTR_EMULATE_PREPARES => false, ]; try { $pdo = new PDO($dsn, $user, $pass, $options); } catch (\PDOException $e) { throw new \PDOException($e->getMessage(), (int)$e->getCode()); } echo "" . date('m/d/y') . ""; $tenant=$_POST['tenant']; $unit=$_POST['unit']; $amtpaid=$_POST['amtpaid']; $hudpay=$_POST['hudpay']; $datepaid=$_POST['datepaid']; /* if no pay or part pay, add $35 to latechg field and amount not paid to prevbal field */ if ($amtpaid < $amtdue) { $amtdue = 0; // $amtdue is not defined in the code $latechg = $latechg + 35.00; $prevbal = $amtdue - $amtpaid; } /* if payment = amtdue */ elseif ($amtpaid == $amtdue) { $prevbal = 0; $latechg = 0; } /* if over-payment subtract over-payment from prevbal */ else { // removed semicolon from else statement $prevbal = $amtpaid - $amtdue; $latechg = 0; } /* Perform a query, check for error */ $sql = "UPDATE paytbl SET amtpaid=?, prevbal=?, latechg=?, datepaid=? WHERE unit=?"; $pdo->prepare($sql)->execute([$amtpaid, $prevbal, $latechg, $datepaid, $unit]); ?>