Query depends on another query inside
<p>I having a problem with a query inside another one.</p>

<p>One table as question and the other one has que questions used by the users.
So I'm Trying to query a new question but only if is not in the used question table. </p>

<p>In this example looks like its working, but i have more than 1000 question on the db Table and cant see if the result is not in the result.</p>

<pre><code>SELECT * FROM questions 
WHERE id NOT IN 
    (SELECT QiD FROM Usedquestion) 
ORDER BY RAND() 
LIMIT 1 
</code></pre>

<p>Can some one send me a light?</p>