ield">dbid</code>
      and <code class="structfield">queryid</code>.  If any of the parameters are not
      specified, the default value <code class="literal">0</code>(invalid) is used for
      each of them and the statistics that match with other parameters will be
      reset.  If no parameter is specified or all the specified parameters are
      <code class="literal">0</code>(invalid), it will discard all statistics.
      If all statistics in the <code class="filename">pg_stat_statements</code>
    