title: How to use count() in Flask-sqlalchemy
body: <p>I am assisting a project which uses flask-sqlalchemy.<br />
  I would like a db query to count the number of records in the table.</p>
  <p>Can I use <code>table.query.filter_by(condition).count()</code> directly?<br />
  Or is there anything that I need to add?</p>
  <p>Please assist me. I am a begineer. Thanks in advance!</p>