A mysql query

[tibberous]

I have two tables, one called categories, one called files.

 

Categories has three fields: id, categoryname and parent

Files has four fields: id, filename, categoryid and categoryname

 

Now, I have a table with all the category id's set - I need to set categoryname = to the categoryname with the id of categoryid.

 

Sorry if that is hard to follow, it is hard to write too.

 

Anyone know how to do this?

[darkfreaks]

 SET categoryname WHERE id='$id'

 

<?php

$id=$_GET['category_id'];

?>

[marcus]

Deh, dark, you should help him out by stopping out a mysql injection.

 

$id = mysql_real_escape_string($_GET['category_id']);

if($id){
   if(ctype_digit($id)){ //if you don't have ctype extension on use intval
   $sql = "SELECT * FROM `table` WHERE `id`='$id'";
   $res = mysql_query($sql) or die(mysql_error());
      if(mysql_num_rows($res) == 0){
      echo "ID does not exist!\n";
      }else {
      $sql2 = "UPDATE `table` SET `field`='new_row' WHERE `id`='$id'";
      $res2 = mysql_query($sql2) or die(mysql_error());
      echo "Updated";
      }
   }else {
   echo "Invalid ID";
   }
}else {
echo "ID not set";
}