Question

 <?php 
/** Connect to DB */
 mysql_connect("localhost", "dbuser", "pass") or die(mysql_error()); 
 mysql_select_db("dbname") or die(mysql_error()); 

$link_id = $_GET['link_id'];

/** increase the counter of the URL*/
mysql_query("UPDATE link_count SET count = count + 1 WHERE ID = $link_id") or die(mysql_error()); 

/** retrieve URL */
$result = mysql_query("SELECT * FROM link_count WHERE ID = $link_id") or die(mysql_error()); 
$row = mysql_fetch_array($result); 

header( "Location:" .$row['URL'] ); 
?>

Of course db info has been changed for posting here. Where I try to use

count.php?link_id=1

in a link I get “Unknown column ‘ID’ in ‘where clause'”

I checked to make sure there were all single quotes instead of backticks….

EDIT: Solution provided by @Kai Qing in a comment to CanSpice’s answer.

Answer 1

Your column is probably named id, not ID. Column names are case-sensitive.