• 2022-10-27
    若查询考试成绩不为空的学生的学号,下列语句哪个是正确的?( )
    A: SELECT Sno FROM SC WHERE Grade >= 0;
    B: SELECT Sno FROM SC WHERE Grade != 0;
    C: SELECT Sno FROM SC WHERE Grade IS NOT NULL;
    D: SELECT Sno FROM SC WHERE Grade NOT IS NULL;
  • 举一反三