Question

I am attempting to identify whether a variable in an array is present, and if it is state that it is “true” and if it is not state that it is “false”. The problem is that I am receiveing a response for all array variables, when I only want to know if the page variable is present in the array with link like http://example.com/product.php?image_id=50

<?php 
$page = $_GET['image_id'];
if (!empty($_SESSION)){
foreach($_SESSION as $name => $value2)   {
  if (substr($name, 0, 7)=='images_') {
  $id = substr($name, 7, (strlen($name)-7));
  $get = mysql_query('SELECT * FROM images WHERE image_id='.mysql_real_escape_string((int)$id));
     while ($cart_info_row = mysql_fetch_assoc($get)) {
        $cart = array('image_id' => $cart_info_row['image_id'],);
        if (in_array($page, $cart)){echo 'true';} else {echo 'false';}
     }
  }
  }
  } 
  }   
?>

Assuming the numbers below are in the SESSION print_r ($cart):

Array ( [image_id] => 42 ) false

Array ( [image_id] => 45 ) false

Array ( [image_id] => 50 ) true

Array ( [image_id] => 49 ) false  

Now, how can I ONLY identify if variable 50 ($page = $_GET['image_id'];)is present with out the other three?

Answer 1

As I understand, your code does 2 things: 1 – checks if key images_$page exists in session and 2 – checks if image with image_id=$page exists in database.

<?php
$page = $_GET['image_id'];
if(isset($_SESSION['images_'.$page]))
{
    $get = mysql_query("SELECT * FROM images WHERE image_id='".mysql_real_escape_string($page)."' LIMIT 1");
    if($cart_info_row = mysql_fetch_row($get))
    {
        echo 'true';
    }
    else
    {
        echo 'false';
    }
}
else
{
    echo 'false';
}

Here isset is used to check if the key images_$page exists in $_SESSION. It is faster than making 2 calls to substr() function.

Also, since we need only checking if given image exists, foreach loop is replaced with if.

After that, a MySQL query runs, and since we need only first match, LIMIT 1 is added to make query faster. Also comparison with image_id is already included in query, so its enough to test if there are returned rows or not (that’s why original while is replaced with if).