$query = "select * from tablename where PRIMARYKEY = 'value' ";
$result = mysql_query($query);
$row = mysql_fetch_assoc ($result);
Now you should be able to access the info using $row['PRIKEY'] or $row['catName'].
If you replace the asterisk with a certain field name, then all you'll get is the value of the fieldname. You need to know the value of the PriKey to get the results of that row and only that row, so replace 'value' with the string you have for the PriKey and you should be on your way.
You will also have access to all fields for that row to use elsewhere in your code.