title: Subtracting n Days from a date using SQL
body: <p>I am quite a beginner when it comes to Oracle. I am having trouble figuring out how to do something similar to this :</p>
  
  <pre><code>SELECT ID, NAME, TO_CHAR(DATEBIRTH, 'DD/MM/YYYY HH24:MI:SS') 
  FROM PEOPLE WHERE DATEBIRTH &gt;= ANOTHERDATE - NDAY
  </code></pre>
  
  <p>To put it short, I want to select everyone who were born N days before a specific date and time but I am not quite sure that this is the way to do it nor that it would give me the results I expect.</p>
  
  <p>PS: I am developping under oracle8i.</p>