public int seek(int number) { score score1 = null; try (Connection c = getConnection(); Statement s = c.createStatement();) { String sql = "select * from (select *,row_number() over (order by [number]) 'x' from 学生成绩信息) as asd where number=" + number; ResultSet rs = s.executeQuery(sql); if (rs.next()) { score1 = new score(); int Chinesegrade = rs.getInt("x"); score1.number = Chinesegrade; } } catch (SQLException e) { e.printStackTrace(); } return score1.number; }各位大佬，String sql = "select * from (select *,row_number() over (order by [number]) 'x' from 学生成绩信息) as asd where number=" + number; 这句SQL语句怎么理解，特别是那 'x'。