updating mysql records based on option selection

Hello I cannot figure out what is wrong w开发者_开发知识库ith my code. Have not much experience with php yet. Can someone please tell me what am I doing wrong??

Here is my code:

<?php
   include 'mysql_connect.php';
if (!isset($_POST['submit'])) {
    $fuelQuery2 = sprintf("UPDATE fuel_price SET `Price` = '%s' WHERE FuelType = '%s' LIMIT 1",
                        mysql_real_escape_string($_POST['inputPrice']),
                        mysql_real_escape_string($_POST['fueltype']));

    $Result = mysql_query($fuelQuery2);
    if($Result){
        echo 'Price has been updated!';
    } else{
        echo 'Failed to update price!';
    }
} else{
    echo 'No form submitted';
}


?>

<h1>Update Oil Price</h1>

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
Oil Price:<input name="inputPrice" type="text" value=""/>

Product
<select name="fueltype">
<option value="Oil">Kero</option>
<option value="Diesel">Diesel</option>
<option value="RedDiesel">Red Diesel</option>
</select>

<input type="submit" name="submit" value="Modify" />
</form>

It's really simple, change

if (!isset($_POST['submit'])) {

to

if(isset($_POST['submit'])) { //Only execute the query when the form is submitted

Your original code told PHP to execute the query when the form wasn't submitted (notice that I removed the !) instead of when it was. The notices you were getting were telling you that the $_POST variables you grabbed for your query didn't exist (because the code ran before the form was submitted).

Also, do look into PDO. The mysql_ family of functions is no longer the preferred method for interacting with the database layer.

PHP

In mysql_connect.php please ensure that you call mysql_connect() and mysql_select_db().

Then you can adjust your code to the following:

<?php
    include 'mysql_connect.php';
    if ('POST' == $_SERVER['REQUEST_METHOD'] and
        isset($_POST['fuel_type']) and
        isset($_POST['oil_price'])) {
        $fuel_type = mysql_real_escape_string($_POST['fuel_type']);
        $oil_price = mysql_real_escape_string($_POST['oil_price']);

        $SQL = "UPDATE `fuel_price`
                SET `Price` = '$oil_price'
                WHERE `FuelType` = '$fuel_type'";

        if(mysql_query($SQL)) {
            echo 'Price updated.';
        } else {
            echo 'Failed to update.';
        }
    }
?>

HTML Form

You don't need PHP_SELF in the action and you can just leave it blank to submit onto the same page.

<form action="" method="post">
    <label for="oil_price">Oil Price</label>
    <input name="oil_price" id="oil_price" type="text" value="" />

    <label for="fuel_type">Product</label>
    <select name="fuel_type" id="fuel_type">
        <option value="Oil">Kerosene</option>
        <option value="Diesel">Diesel</option>
        <option value="RedDiesel">Red Diesel</option>
    </select>

    <input type="submit" name="submit" value="Modify" />
</form>