code: protected String getSortExpression(TableAlias users, CmsUserSearchParameters searchParams) {
  
          SortKey sortKey = searchParams.getSortKey();
          String ordering = users.column(colId());
          if (sortKey != null) {
              switch (sortKey) {
                  case email:
                      ordering = users.column(colEmail());
                      break;
                  case loginName:
                      ordering = users.column(colName());
                      break;
                  case fullName:
                      ordering = getUserFullNameExpression(users);
                      break;
                  case lastLogin:
                      ordering = users.column(colLastLogin());
                      break;
                  case orgUnit:
                      ordering = users.column(colOu());
                      break;
                  case activated:
                      ordering = getUserActivatedExpression(users);
                      break;
                  case flagStatus:
                      ordering = getUserFlagExpression(users, searchParams.getSortFlags());
                      break;
                  default:
                      break;
  
              }
          }
          return ordering;
      }
docs: Returns the expression used for sorting the results.<p>
  
  @param users the user table alias
  @param searchParams the search parameters
  
  @return the sorting expressiong