<form action="?id=usercp" method="post"> 
<textarea name="bio"> 
 
</textarea> 
<input type="submit" value="Submit"> 
</form> 

$bio = htmlspecialchars($_POST['bio']); 
 
$query = "INSERT INTO users (bio) 
values('" . $bio . "')"; 
mysql_query($query) or die(mysql_error()); 

<?php 
$bio = htmlspecialchars($_POST['bio']);  
$bio2 = addslashes($bio); 
$query = "UPDATE users SET bio='".$bio2."' WHERE username='".$username."'";  
mysql_query($query) or die(mysql_error()); 
?> 

<?php 
echo "I\'m Peter"; 
?> 

function register()  
{  
$query = "INSERT INTO users (user, password, usergroup, email, regdate)   
values('" . $_POST['user'] . "', '" . $_POST['password'] . "', 'user', '" . $_POST['email'] . "', CURDATE()";  
} 

//Add the user into the users MySQL table 
function register() 
{ 
$query = "SELECT * FROM users  
WHERE user='" . $_POST['user'] . "'"; 
$result = mysql_query($query); 
$rowcount = mysql_num_rows($result); 
 
$query = "SELECT * FROM users  
WHERE email='" . $_POST['email'] . "'"; 
$result = mysql_query($query); 
$rowcount2 = mysql_num_rows($result); 
 
if($rowcount != 0) 
{ 
echo "The username you entered is taken... please enter another. "; 
} 
 
elseif($rowcount2 != 0) 
{ 
echo "The email you entered is taken... please enter another. "; 
} 
 
else 
{ 
$query = "INSERT INTO users (user, password, usergroup, email)  
values('".$_POST['user']."', '".md5($_POST['password'])."', 'user', '".$_POST['email']."')"; 
mysql_query($query); 
} 
} 

<?php 
if($rowcount != 0)  
{  
echo "The username you entered is taken... please enter another. ";  
} 
if($rowcount2 != 0)  
{  
echo "The email you entered is taken... please enter another. ";  
}  
?> 

<?php 
$query = "SELECT * FROM users LIMIT 3";  
?> 

<?php 
$query = "SELECT * FROM users LIMIT 0, 3";  
?> 

Apparently since UPDATE is a MySQL command you can't name a column that. xD 

<?php 
if(isset($_POST['postid'])) 
{ 
	$post = mysql_real_escape_string(htmlspecialchars($_POST['post'])); 
	$title = mysql_real_escape_string(htmlspecialchars($_POST['title'])); 
	$pid = mysql_real_escape_string(htmlspecialchars($_POST['postid'])); 
	 
	$query = "UPDATE posts SET title='$title' and post='$post' 
	WHERE id='$pid'"; 
	 
	mysql_query($query) or die(mysql_error()); 
	echo "Two."; 
} 
 
elseif(isset($_GET['pid'])) 
{ 
	$pid = $_GET['pid']; 
	echo "One."; 
} 
	$query = "SELECT * FROM posts WHERE id='" . $pid ."'"; 
	 
	$result = mysql_query($query) or die(mysql_error()); 
	 
	$array = mysql_fetch_array($result); 
	 
 
?> 
<form action="?id=edit" method="post"> 
<table> 
	<tr> 
		<td> 
		<input type="text" name="title" class="text" value="<?php echo $array['title']; ?>" /> 
		<input type="text" name="postid" class="hidden" value="<?php echo $array['id']; ?>" /> 
		</td> 
	</tr> 
 
	<tr> 
		<td> 
		<textarea name="post" class="text"> 
		<?php 
		echo $array['post']; 
		?> 
		</textarea> 
		</td> 
	</tr> 
	 
	<tr> 
		<td> 
		<input type="submit" value="Submit" /> 
		</td> 
	</tr> 
</table> 
</form> 

$query = "SELECT * FROM posts WHERE id=".$pid; 
$query = "UPDATE posts SET title='$title' and post='$post' 
WHERE id=".$pid; 

<?php 
if (isset($_GET['pid']))  
{ 
	$pid = (int) $_GET['pid']; 
    if (isset($_POST['submit']))  
    { 
        $post = mysql_real_escape_string(htmlspecialchars($_POST['post'])); 
        $title = mysql_real_escape_string(htmlspecialchars($_POST['title'])); 
	    $query = "UPDATE posts SET title = '$title', post = '$post' WHERE id = $pid;"; 
        mysql_query($query); 
	    if (mysql_affected_rows()) 
        { 
	        echo 'Updated'; 
        } 
        else 
        { 
            echo '<p>Failed to edit the post.</p>'; 
        } 
    } 
 
    $query = "SELECT * FROM posts WHERE id = '{$pid}';"; 
    $result = mysql_query($query); 
    if (mysql_num_rows($result)) 
    { 
        $array = mysql_fetch_array($result);  
?>  
<form action="?id=edit&pid=<?php echo $pid; ?>" method="post">  
<table> 
	<tr>  
		<td><input type="text" name="title" class="text" value="<?php echo $array['title']; ?>" /></td>  
	</tr>  
  
	<tr>  
		<td><textarea name="post" class="text"><?php echo $array['post']; ?></textarea> </td>  
	</tr>  
	  
	<tr>  
		<td><input type="submit" name="submit" value="Submit" /> </td>  
	</tr> 
</table>  
</form> 
<? 
    } 
    else 
    { 
        echo 'The post does not exist.'; 
    } 
} 
else 
{ 
    echo '<p>You have not specified a post to edit.</p>'; 
} 
?>