/**
  * Display the general status log table.
  *
  * @param int $pagesize
  * @param bool $useinitialsbar
  */
 public function render($pagesize, $useinitialsbar = true)
 {
     $columns = array('owner', 'for_user_email', 'senddate', 'enrolperiod', 'submission_code', 'course', 'cohorts', 'groups', 'issend');
     if ($this->filter === self::UNUSED) {
         $columns[] = 'action';
     }
     $this->define_table_columns($columns);
     // Generate SQL.
     $fields = 'c.*, ' . get_all_user_name_fields(true, 'u');
     if ($this->filter === self::UNUSED) {
         $fields .= ', NULL as action';
     }
     $from = '{block_coupon} c LEFT JOIN {user} u ON c.ownerid=u.id';
     $where = array();
     $params = array();
     if ($this->ownerid > 0) {
         $where[] = 'c.ownerid = ?';
         $params[] = $this->ownerid;
     }
     switch ($this->filter) {
         case self::USED:
             $where[] = 'c.userid IS NOT NULL AND c.userid <> 0';
             break;
         case self::UNUSED:
             $where[] = 'c.userid IS NULL';
             break;
         case self::ALL:
             // Has no extra where clause.
             break;
     }
     parent::set_sql($fields, $from, implode(' AND ', $where), $params);
     $this->out($pagesize, $useinitialsbar);
 }