Something wrong while deleting data from DB - php

Question

I'm trying to delete some information from the database, but when I ask the user to confirm action, something goes wrong. Can you help me?
The script prints the categories to choose if nothing is settled. Then, It asks the user to delete or not delete the categories chosen. In the end, it deletes what was chosen.
But there's some error in the last part(first in the script) and I cannot understad where it's going wrong:
<?php
//If the user confirm to delete...
if(isset($_POST['eliminazione_conferma']) and $_POST['eliminazione_conferma']=='conferma'){
//if conferma_eliminazione=1, don't delete
if(isset($_POST['conferma_eliminazione']) and $_POST['conferma_eliminazione']=='1'){
echo 'Eliminazione annullata';
}else{//Delete if conferma_eliminazione=0
while($row=$categoria){
$delete= "DELETE FROM categorie WHERE $row = category_id";
$query=mysql_query($delete);
echo "$row eliminato\n";
}
}
}else{//ELSE, print the form to confirm action
if(isset($_POST['eliminazione']) and $_POST['eliminazione']=='delete'){
//Array with the chosen "categories"
$categoria=isset($_POST['categoria']) ? $_POST['categoria'] : array();
//Print the chosen categories to ask confirmation
echo'Sicuro di voler eliminare le seguenti categoire?<br />';
foreach($categoria as $row){
echo "$row<br />\n";
}
//Yes = 0, No = 1
echo '<form method="post" action="',$_SERVER['REQUEST_URI'],'">
<input type="radio" name="conferma_elimiazione" value="0" />Si<br />
<input type="radio" name="conferma_eliminzione" value="1" />No<br />
<input type="hidden" name="eliminazione_conferma" value="conferma" />';
foreach($categoria as $row){
echo'<input type="hidden" name="categoria[]" value="',$row,'" />',"\n",'' ;
}
echo'
<input type="submit" value="Conferma" />
</form>';
}else{//In the end, if nothing is settled, print the form to check the category to delete
//Select the categories from the database
echo'<form method="post" action="',$_SERVER['REQUEST_URI'],'" />',"\n",'';
$select = "SELECT nome,category_id FROM categorie ORDER BY category_id" ;
$select_result=mysql_query($select) or die("Mysql Error: ".mysql_error());
while($row = mysql_fetch_assoc($select_result)){
echo '<input type="checkbox" name="categoria[]" value="',$row['category_id'],'">',$row['nome'],'<br />';
}
echo'<input type="hidden" name="eliminazione" value="delete" />
<input type="submit" name="submit" value="Elimina" />
</form>';
}
}

Answer 1

The problem with the query
$delete= "DELETE FROM categorie WHERE $row = category_id";
is
here
WHERE $row = category_id";
What is category_id?
Do you have a value for that?
Probably you want WHERE category_id=/*something here like $row['column_name']*/

Answer 2

Thanks everyone for the help, but I've solved my problem in this way(the script wasn't transformig the value of "conferma_eliminazione" in the integer type):
<h2>Modifica o Elimina Categoria </h2>
<?php
if(isset($_POST['eliminazione_conferma']) and $_POST['eliminazione_conferma']=='conferma'){
$categoria=isset($_POST['categoria']) ? $_POST['categoria'] : array();
$a=(int)$_POST['eliminazione'];
if($a=='1'){
echo 'Eliminazione annullata';
echo "\n";
}elseif($a=='0'){
foreach($categoria as $row){
$delete= "DELETE FROM categorie WHERE $row = category_id";
$query=mysql_query($delete);
echo "$row eliminato\n";
}
}
}else{
if(isset($_POST['eliminazione']) and $_POST['eliminazione']=='delete'){
$categoria=isset($_POST['categoria']) ? $_POST['categoria'] : array();
echo'Sicuro di voler eliminare le seguenti categoire?<br />';
foreach($categoria as $row){
echo '',$row,'<br />',"\n";
}
echo '<form method="post" name="form_eliminazione_categoria" action="',$_SERVER['REQUEST_URI'],'">',"\n",'
<input type="radio" name="eliminazione" value="0" />Si<br />' ,"\n",'
<input type="radio" name="eliminazione" value="1" />No<br />',"\n",'
<input type="hidden" name="eliminazione_conferma" value="conferma" />',"\n",'';
foreach($categoria as $row){
echo '<input type="hidden" name="categoria[]" value="',$row,'" /><br />',"\n",'';
}
echo'
<input type="submit" value="Conferma" />
</form>';
}else{
echo'<form method="post" action="',$_SERVER['REQUEST_URI'],'" />',"\n",'';
$select = "SELECT nome,category_id FROM categorie ORDER BY category_id" ;
$select_result=mysql_query($select) or die("Mysql Error: ".mysql_error());
while($row = mysql_fetch_assoc($select_result)){
echo '<input type="checkbox" name="categoria[]" value="',$row['category_id'],'">',$row['nome'],'<br />';
echo "\n";
}
echo'<input type="hidden" name="eliminazione" value="delete" />',"\n",'
<input type="submit" name="submit" value="Elimina" />',"\n",'
</form>';
}
}