private void 学生成绩查询_Load(object sender, EventArgs e)
{
DataTable dt = op.GetDataTable("select score.sno,sname,course.cno,cname,ccategory,score.grade from score,student,course where student.sno=score.sno and score.cno=course.cno", "student");
dataGridView1.DataSource = dt;
}
