学生选课数据库中有如下学生表： 学生表（学号，姓名，专业） （对应的英文表示：student(sno,sname,specialty)） 如果要查询各专业的学生人数，下列查询语句中，正确的是（ ）。
A: SELECT specialty,count(*) FROM student order by specialty;
B: SELECT count(specialty) FROM student order by specialty;
C: SELECT specialty,count(*) FROM student group by specialty;
A: SELECT specialty,count(*) FROM student order by specialty;
B: SELECT count(specialty) FROM student order by specialty;
C: SELECT specialty,count(*) FROM student group by specialty;
举一反三
- 从Student中查询出各专业学生的入学录取平均分，显示“专业”和“平均分”两列，保留一位小数。SELECT Specialty AS ① ,平均分=str( ② (AScores),5,1)FROM StudentGROUP BY ③
- 在学生选课数据库中，查询选修了课程的学生的学号、姓名，SQL语句可为（ ） A: SELECT DISTINCT Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno; B: SELECT Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno; C: SELECT DISTINCT Sno, DISTINCT Sname FROM Student WHERE Student.Sno IN (SELECT Sno FROM SC); D: SELECT Sno, Sname FROM Student WHERE Student.Sno IN (SELECT DISTINCT Sno FROM SC);
- 现要利用Student（sno, sname, ssex, sage, sdept）表查询年龄最小的学生的姓名和年龄。下列实现此功能的查询语句正确的是（ ）。 A: SELECT sname, Min( sage ）from student B: SELECT sname ,sage from student where sage=Min( sage ) C: SELECT TOP 1 Sname , Sage From student D: SELECT TOP 1 sname , sage from student order by sage
- 对于学生信息表：student(sno，sname，sex，age，grade)，查询学习成绩为空的学生的学号和姓名，下面语句正确的是 A: SELECT sno，sname FROM student WHERE grade=NULL B: SELECT sno，sname FROM student WHERE grade IS NULL C: SELECT sno，age FROM student WHERE grade IS NULL D: SELECT sno，age FROM student WHERE grade=NULL
- 查找学生表student中姓名的第二个字为“t”的学生学号sno和姓名sname，下面SQL语句正确的是（）。 A: SELECT sno, sname FROM student WHERE sname='_t%'; B: SELECT sno, sname FROM student WHERE sname LIKE '_t%'; C: SELECT sno, sname FROM student WHERE sname＝'%t_'; D: SELECT sno, sname FROM student WHERE sname LIKE '%t_';