PHP - How To Retrive This Sql On Php

hi
this is my code but I can't see the array in echo
<table>
<tr>
<td>
<h3>
<?php
//if the cart is empty show the message
if (!$cart && !$_POST['item']) {
echo "No cart available.";
$cart = array();
}
else{
               
//if the new item added to the cart let the customer knows   
if ($_POST['item']) {
echo "Added to your cart: " . $_POST['item'];
}
}
?>   
</h3>
</td>
</tr>
<tr>
<?php
//if the cart isn't empty show the cart   
if ($cart) {
$cart[] = $_POST['item'];}
 foreach($cart as $key => $value) {
echo'<td>
<img src="images/'.$value.'.jpg" alt="'.$value.'" />
</td>
<td>
<form>
<p>
'.$value.' =
<input type="text" size="2" name="number" value="1" />
</p>
</form>
</td>
<td>
<form method="post" action="update.php">
<p>
<input type="submit" name="submit" value="Update This One Item" />
</p>
<form>
</td> <br />';
}
?>
</tr>
</table>

Hello,
this is my first time on this forum and also a modest newb on php, but i heard alot of people i know visit this site to get help on php. So i have a question, i know how to submit a form to mysql, the question is how do i recieve each indivual data i submit with the form by date and display it in order by date. i would like to submit kind of a status up everyday similar to twitter but order it by date and have it look kinda like:

July 5, 2006

This is a status example text that i will sumbit via form, links can be clicked and etc.
This is a status example text that i will sumbit via form, links can be clicked and etc.
This is a status example text that i will sumbit via form, links can be clicked and etc.

July 4, 2006

This is a status example text that i will sumbit via form, links can be clicked and etc.
This is a status example text that i will sumbit via form, links can be clicked and etc.

hi all,

mine http call :
<script type="text/javascript">
var leadidarray =new Array();
leadidarray[1] = 100;
leadidarray[2] = 200;
leadidarray[3] = 300;
leadidarray[4] = 400;
leadidarray[5] = 500;
var url = 'test.php?query=test&leadarray='+leadidarray;
       $.getJSON(url,function(data){});
<script>

Now on the processing page i am getting

$row = $_GET[leadarray] ;
   var_dump($_GET[leadarray]); or print_r( $_GET[leadarray] ); gives me values 100,200,300,400,500

but i want all that separate variables or all values in array so i can compare with another array, how can i do that?

CREATE TABLE posts (
postId INT(11) NOT NULL UNIQUE AUTO_INCREMENT,	
title VARCHAR(255) NOT NULL,
author VARCHAR(24) NOT NULL,	
description TEXT NOT NULL,       
createdAt TIMESTAMP,
PRIMARY KEY (postId)    
);
CREATE TABLE comments(
commentId INT(11) NOT NULL UNIQUE AUTO_INCREMENT,    
comment  TEXT NOT NULL,
postId INT(11),
userId INT(11),
createdAt TIMESTAMP,	
PRIMARY KEY (commentId),
FOREIGN KEY (userId) REFERENCES users(userId),
FOREIGN KEY (postId) REFERENCES posts(postId)   
);
CREATE TABLE replies (
repId INT(11) NOT NULL UNIQUE AUTO_INCREMENT,   
reply  TEXT NOT NULL,
userId INT(11),
commentId INT(11), 	
createdAt TIMESTAMP,     
PRIMARY KEY (repId),
FOREIGN KEY (userId) REFERENCES users(userId),
FOREIGN KEY (commentId) REFERENCES comments(commentId)     
);
CREATE TABLE users (
userId INT(11) NOT NULL UNIQUE AUTO_INCREMENT,
userName VARCHAR(100) NOT NULL,,	          
email VARCHAR(100) NOT NULL,
PRIMARY KEY (userId)
);

how to retrive userName,comment, and createdAt from users and comments table while I have used userId as a  Foreign key on the comment table

if it isn't correct, correct me please