title: Flask SQLAlchemy between query return empty list
body: <p>I just got started using Flask SQLAlchemy and I looked over here to see how I am supposed to do a query between so I found <a href="https://stackoverflow.com/questions/8895208/sqlalchemy-how-to-filter-date-field">this </a></p>
  
  <p>But the problem that I got is that it returns the following when executes as below:</p>
  
  <pre><code>SELECT records.id AS records_id, records.created_at AS records_created_at, records.file_type AS records_file_type, records.path_filename AS records_path_filename 
  FROM records 
  WHERE records.created_at BETWEEN ? AND ?
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code>today_date = datetime.today().strftime("%d/%m/%Y")
  week = (datetime.today() - timedelta(days=7)).strftime("%d/%m/%Y")
  month = (datetime.today() - timedelta(days=30)).strftime("%d/%m/%Y")
  
  last_30_days = db.session.query(Records).filter(Records.created_at.between(month, today_date))
  </code></pre>
  
  <p>And when I add <code>.all()</code> at the end of the last_30_days expression it returns an empty list.</p>
  
  <p>I would also like to mention that when I use just the same expression to query the week, today_date it gets all the results.</p>
  
  <p>This is how the table looks like:</p>
  
  <pre><code>class Records(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      created_at = (db.Column(db.String(20), nullable=False))
      file_type = (db.Column(db.String(100), nullable=False))
      path_filename = db.Column(db.String(120), unique=True, nullable=False)
  </code></pre>
  
  <p>Could anybody explain to me please what's going on? Thanks!</p>