title: '' is not valid floating point value delphi
body: <p>error message thrown</p>
  
  <p><img src="https://i.stack.imgur.com/h0pEA.jpg" alt="enter image description here"></p>
  
  <pre><code>` qConsulta2 := TQuery.Create(Application);
    qConsulta2.DatabaseName := 'BaseDato';
    qConsulta2.SQL.Text := 'select VALOR from PARAMETRO where codigoPARAMETRO  = ''IVA'' ';
    qConsulta2.open;
    qCompraDetalle.FieldByName('PORCENTAJE_IVA').AsFloat:=        qConsulta2.fieldbyname('valor').asfloat;
    qConsulta2.close;
    qConsulta2.free `
  </code></pre>
  
  <p>This threw me into execution this error, and do not know why, beforehand thank you very much for your time and help. Excuse me for my bad English.</p>