code: func (n *NamedStmt) QueryRow(arg interface{}) *Row {
  	args, err := bindAnyArgs(n.Params, arg, n.Stmt.Mapper)
  	if err != nil {
  		return &Row{err: err}
  	}
  	return n.Stmt.QueryRowx(args...)
  }
docs: // QueryRow executes a named statement against the database.  Because sqlx cannot
  // create a *sql.Row with an error condition pre-set for binding errors, sqlx
  // returns a *sqlx.Row instead.
  // Any named placeholder parameters are replaced with fields from arg.