title: Using function least and greatest on timestamp in PostgreSQL
body: <p>How can I use function least/greatest in PostgreSQL on timestamp column?<br>
  I have a column - plc_time (timestamp without time zone) and I need to select rows where the plc_time is greatest from two values (the value is timestamp without time zone).<br>
  Should I use the conversion? How can I do it?</p>