POST and GET at the same time - php

Question

hello everyone sorry but am just beginner in php , mysql ... i was developing question and answer website which i have page for all Question (Q.php) and page for displaying a specific question (QR.php) and get information according to data sent from Q.php via url ($_GET['start'] i also have page to confirm that the answer is already submitted .... but i got error when entering the id from get method and the message from post method ... any answer will be appreciated
Q.php
<?php
include("pagination.php");
if(isset($res))
{
while($result = mysql_fetch_assoc($res))
{
echo '<div class="shop-item">' ;
echo ' <div class="price">' ;
echo $result['Inquirer'] ;
echo ' </div>' ;
echo ' <div class="price">' ;
echo $result['question'] ;
echo ' </div>' ;
echo ' <div class="actions"> ';
echo '<input type="button" class="btn btn-large " value="More Info" onclick="window.location=\'QR.php?start=' . urlencode($result['id']) . ' \';" />';
echo '</div> ';
echo ' </div> ';
}
}
?>
QR.php
<form action="QRR.php" method="POST">
<div class="blog-post blog-single-post">
<div class="single-post-title">
<h2>Post Your Answer</h2>
</div>
<div align="Right">
<textarea class="form-control" rows="4" name ="answer" id="Test">
</textarea>
<br>
<div class="actions">
<?php echo '<input type="button" class="btn btn-large " value="Post Answer" onclick="window.location=\'QRR.php?start=' . urlencode($_GET['start']) . ' \';" />'; ?>
</div>
</div>
</div>
</form>
QRR.php
<?php
// variables
$answer=$_REQUEST['answer'];
require ("coonection.php");
$FURL = $_REQUEST['hi'];
//query
$query = "INSERT INTO `answers`(`answer_id`, `question_id`, `answer`, `answerer`, `rate`, `dnt`) VALUES ('','$FURL','$answer','ahmed','',CURRENT_TIMESTAMP)";
$data=mysql_query($query) or die(mysql_error());
if($data)
{
echo "Your Questions Has Been Successfully Added ";
}
?>
if i removed passing hi from QR to QRR answer stored //$answer
if i removed storing answer from the text area the id from url stroed //$FURL

Answer 1

This isnt the most beautiful code, as i just copied yours and made a few modifications.. but this form will submit back to the same page, and the php will run and insert ONLY if the form is submitted.
if(isset($_POST['answer'])) says "if the variable _POST answer is set, run the php code and insert.. if it is not set, do nothing.
You will notice the form action is left blank, you can set it to the page name yo are on.. as the form will send the variables to the same page. This is a good way of doing it because if there are errors, you can prepopulate the input or textareas with the code they just typed in.
<?php
// variables
if(isset($_POST['answer'])){
$answer=$_POST['answer'];
require ("coonection.php");
$FURL = $_POST['hi']; // there is no input name 'hi' set in your form. so this code will fail due to that.
//query
$query = "INSERT INTO `answers`(`question_id`, `answer`, `answerer`, `rate`, `dnt`) VALUES ('$FURL','$answer','ahmed','',CURRENT_TIMESTAMP)";
$data=mysql_query($query) or die(mysql_error());
if($data){
echo "Your Questions Has Been Successfully Added ";
}
}
?>
`
you will see i removed your answer_id. if you use this code, make sure that field is set to primary auto increment in your database.
<form action="" method="POST">
<div class="blog-post blog-single-post">
<div class="single-post-title">
<h2>Post Your Answer</h2>
</div>
<div align="Right">
<textarea class="form-control" rows="4" name="answer" id="Test"></textarea>
<br>
<div class="actions">
<button type="submit" class="btn btn-large " value="Post Answer">Post Answer</button>
</div>
</div>
</div>
</form>
NOTE: both of these snippets will go in the same page.