Update query not working PHP MySQL - php

Question

Can anybody help me understand why this update query isn't updating the fields in db.
<?php
$id= $_GET['id'];
$query1 = mysql_query("SELECT * FROM invoice WHERE id=$id limit 1");
?>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<div class="card">
<div class="card-header">
<strong>Create Tax</strong>
</div> <?php
while($query2=mysql_fetch_array($query1)){
// $results = mysql_fetch_array($raw_results) puts data from database into array, while it's valid it does the loop
?>
<div class="card-block">
<div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer Name</label>
<input type="text" class="form-control" id="company" name="cname" value="<?php echo $query2['CustomerName']?>" placeholder="Coustomer Name">
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer Mobile </label>
<input type="text" class="form-control" id="company" name="mobile" value="<?php echo $query2['CustomerMobile']?>" placeholder="Coustomer Mobile">
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<label for="company">Email</label>
<input type="text" class="form-control" id="company" name="email" value="<?php echo $query2['Email']?>" placeholder="Email">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer Streat </label>
<input type="text" class="form-control" id="company" name="streat" value="<?php echo $query2['CustomerStreat']?>" placeholder="Coustomer Streat">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer City</label>
<input type="text" class="form-control" id="company" name="city" value="<?php echo $query2['CustomerCity']?>" placeholder="Coustomer City">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer State</label>
<input type="text" class="form-control" id="company" name="state" value="<?php echo $query2['CustomerState']?>" placeholder="Coustomer State">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Coustomer Country</label>
<input type="text" class="form-control" id="company" name="country" value="<?php echo $query2['CustomerCountry']?>" placeholder="Coustomer Country">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Zip/Pin Code</label>
<input type="text" class="form-control" id="company" name="pin" value="<?php echo $query2['ZipCode']?>" placeholder="ZipCode">
</div>
</div>
<?php } ?>
<div class="col-sm-6">
<div class="form-group">
<label for="company">Tax Name </label><?php
$query1 = mysql_query("SELECT * FROM Tax");
?>
<select id="select" name="tax" class="form-control" size="1"><?php
while($query2=mysql_fetch_array($query1)){
// $results = mysql_fetch_array($raw_results) puts data from database into array, while it's valid it does the loop
?>
<option value="<?php echo $query2['NameOfTax']?> , <?php echo $query2['TaxPercentage']?>"><?php echo $query2['NameOfTax']?> , <?php echo $query2['TaxPercentage']?></option>
<?php $taxvalue = $query2['TaxPercentage']; ?> <?php } ?>
</select>
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Iteam Name </label>
<input type="text" class="form-control" id="company" name="item" placeholder="Iteam Name" value="<?php echo $query2['ItemName']?>">
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<label for="company">Iteam Price </label>
<input type="text" class="form-control" id="company" name="itemprice" placeholder="Iteam price" value="<?php echo $query2['ItemPrice']?>">
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<label for="company">Paid Ammount </label>
<input type="text" class="form-control" id="company" name="pammount" placeholder="Paid Ammount" value="<?php echo $query2['PaidAmmount']?>">
</div>
</div> <div class="col-sm-6">
<div class="form-group">
<label for="company">Date</label>
<input type="text" class="form-control" id="company" name="date" placeholder="Date" value="<?php echo $query2['Date']?>">
</div>
</div>
<div class="col-sm-12">
<input type="submit" class="btn btn-outline-success" name="submit" value="Processe Invoice"/>
</div>
</div>
</div>
</div>
</div>
<!--/col-->
</form>
<?php
$cname = $_POST['cname'];
$mobile = $_POST['mobile'];
$email = $_POST['email'];
$streat = $_POST['streat'];
$city = $_POST['city'];
$state = $_POST['state'];
$country = $_POST['country'];
$pin = $_POST['pin'];
$tax = $_POST['tax'];
$item = $_POST['item'];
$itemprice = $_POST['itemprice'];
$percent = ($taxvalue / 100) * $itemprice ;
$tammount = $percent + $itemprice;
$pammount = $_POST['pammount'];
$uammount = $tammount - $pammount;
$date = $_POST['date'];
$ip = $_SERVER['REMOTE_ADDR'];
$date1 = date('h,i,s');
if(isset($_POST['submit']))
{
$sql = "UPDATE `ero`.`invoice` SET `CustomerName` = '$cname', `CustomerMobile` = '$mobile', `Email` = '$email', `CustomerStreat` = '$streat', `CustomerCity` = '$city', `CustomerState` = '$state', `CustomerCountry` = '$country', `ZipCode` = '$pin', `TaxName` = '$tax', `ItemName` = '$item', `ItemPrice` = '$itemprice', `TotalAmmount` = '$tammount', `PaidAmmount` = '$pammount', `UnpaidAmmount` = '$uammount', `Date` = '$date', `IP` = '$ip', `DateTime` = '$date1' WHERE `invoice`.`id` = '$id'";
$result = mysql_query($sql);
if($result)
$url='customer.php';
echo '<script>window.location = "'.$url.'";</script>';
die;
}
?>
invoice.php
<?php
$query1 = mysql_query("SELECT * FROM invoice");
?>
<table class="table table-bordered table-striped table-condensed">
<thead>
<tr>
<th>Customer Name</th>
<th>Mobile</th>
<th>Email</th>
<th>City</th>
<th>Item Name</th>
<th>Item Price</th>
<th>Tax</th>
<th>Total Ammount</th>
<th>Paid Ammount</th>
<th>Unpaid Ammount</th>
<th>Action</th>
</tr>
</thead>
<tbody><?php
while($query2=mysql_fetch_array($query1)){
// $results = mysql_fetch_array($raw_results) puts data from database into array, while it's valid it does the loop
?>
<tr>
<td><?php echo $query2['CustomerName']?></td>
<td><?php echo $query2['CustomerMobile']?></td>
<td><?php echo $query2['Email']?></td>
<td><?php echo $query2['CustomerCity']?></td>
<td><?php echo $query2['ItemName']?></td>
<td><?php echo $query2['ItemPrice']?></td>
<td><?php echo $query2['TaxName']?></td>
<td><?php echo $query2['TotalAmmount']?></td>
<td><?php echo $query2['PaidAmmount']?></td>
<td <?php if ($query2['UnpaidAmmount'] > 1) echo 'style="background-color:#FF0000"' ?>><?php if ($query2['UnpaidAmmount'] < 1) echo "Ammount Paid"; else echo $query2['UnpaidAmmount'];?></td>
<td>
<button type="button" class="btn btn-outline-danger btn-sm"><a href="DeleteInvoice.php?id='<?php echo $query2['id'] ?>'" >Delete</a>
<button type="button" class="btn btn-outline-success btn-sm"><a href="ViewInvoice.php?id='<?php echo $query2['id'] ?>'" >View</a></button>
<button type="button" class="btn btn-outline-success btn-sm"><a href="updatecheck.php?id='<?php echo $query2['id'] ?>'" >Update</a></button>
</div> </td> </tr> <?php } ?>
<tr>
this scripts redirects customer.php.if i place a manual id like id = 38. its wroking. but there is no update in MySql Table.i am new to programming please explain with some code examples.
Thanks

Answer 1

Replace single quote in the query with double quotes and since you are already using the double quotes for the query, escape the double quotes for the variables or use string concatenation.
<?php
$id = $_GET['id'];
$cname = $_POST['cname'];
$mobile = $_POST['mobile'];
$email = $_POST['email'];
$streat = $_POST['streat'];
$city = $_POST['city'];
$state = $_POST['state'];
$country = $_POST['country'];
$pin = $_POST['pin'];
$tax = $_POST['tax'];
$item = $_POST['item'];
$itemprice = $_POST['itemprice'];
$percent = ($taxvalue / 100) * $itemprice;
$tammount = $percent + $itemprice;
$pammount = $_POST['pammount'];
$uammount = $tammount - $pammount;
$date = $_POST['date'];
$ip = $_SERVER['REMOTE_ADDR'];
$date1 = date('h,i,s');
if (isset($_POST['submit']))
{
$sql = "UPDATE `ero`.`invoice` SET `CustomerName` = \"$cname\", `CustomerMobile` = \"$mobile\", `Email` = \"$email\", `CustomerStreat` = \"$streat\", `CustomerCity` = \"$city\", `CustomerState` = \"$state\", `CustomerCountry` = \"$country\", `ZipCode` = \"$pin\", `TaxName` = \"$tax\", `ItemName` = \"$item\", `ItemPrice` = \"$itemprice\", `TotalAmmount` = \"$tammount\", `PaidAmmount` = \"$pammount\", `UnpaidAmmount` = \"$uammount\", `Date` = \"$date\", `IP` = \"$ip\", `DateTime` = \"$date1\" WHERE `invoice`.`id` = \"$id\"";
$result = mysql_query($sql);
if ($result) $url = 'customer.php';
echo '<script>window.location = "' . $url . '";</script>';
die;
?>

Answer 2

UPDATE table
SET col_name = 'new value'
WHERE condition
this is the syntax for updating in sql, try deleting the ``