title: Form date input from(date) to(date) or I don't know for one or both choices
body: <p>Hi Im new in coding and I have some training project which include MySQL database input from HTML form.
  Its like log of games you played. 1st date input is when you start play and second date input is when you finished game. But I need checker or something similar for both options like "I don't know".
  So displayed information can look like: From: unknown - To: 2019-12-06. </p>
  
  <p>How I make form for this? My MySQL columns are from, to, do I need more? And how I display unknown with PHP if one date is empty?</p>