title: SQLIte compare datetime
body: <p>What is the easiest way in ios app to compare datetime string in sqlite3.
  I store the datetime string in following way.</p>
  
  <pre><code>NSDateFormatter* df=[[NSDateFormatter alloc] init];
      [df setDateFormat:@"yyyy-MM-dd HH:mm"];
      NSString* dtString=[df stringFromDate:[NSDate date]];
  </code></pre>
  
  <p>then I'm inserting dtString into the table. So after i want to retrieve all rows for example only for last two days.</p>