选择单行

I am storing forum post into a database and need to select the last row which got added.

I have a id field which is on auto_increment so what I need to do is do a select were the id is the highest and the topic = 1.

Here is what I got so far which does not echo out anything.

$statementt56 = $db->prepare("SELECT *  FROM topics WHERE topic_cat  = '1' ORDER BY topic_id DESC LIMIT 1  ");
$battle_gett56 = $statementt56->fetch(); 
echo $battle_gett56['topic_subject'] ;

What am i doing wrong ?

I have fixed this by using this code

$statementt = $db->prepare("SELECT *  FROM topics WHERE topic_cat = '1' ORDER BY topic_id DESC LIMIT 1  ");
$statementt->execute(array());
$battle_gett = $statementt->fetch(); // Use fetchAll() if you want all results, or just iterate over the statement, since it implements Iterator
echo $battle_gett['topic_subject'] ;

all works perfect now