查询“学生选课”数据库，输出需要补考的学生姓名。 对应的SQL语句如下： SELECT sname FROM studentinfo WHERE sno =______ (SELECT sno FROM elective WHERE score<60); 下划线应填入的是：
举一反三
- 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);
- 查询选修1号课程的学生姓名的sql语句为： select sname from student where sno = (select sno from sc where cno=1);
- 有关系S(SNO, SNAME, SAGE)，C(CNO, CNAME)，SC(SNO, CNO, GRADE)。其中SNO是学生号，SNAME是学生姓名，SAGE是学生年龄， CNO是课程号，CNAME是课程名称，GRADE是成绩。以下（ ）SQL语句可以实现查询选修了'C002'号课程的学生姓名。 A: SELECT SNAME FROM S, SC WHERE S.SNO=SC.SNO AND CNO='C002' B: SELECT SNAME FROM S WHERE SNO IN (SELECT SNO FROM SC WHERE CNO='C002') C: SELECT SNAME FROM S WHERE SNO = (SELECT SNO FROM SC WHERE CNO='C002') D: SELECT SNAME FROM S WHERE SNO NOT IN (SELECT SNO FROM SC WHERE CNO='C002')
- 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_';
- 有如下的SQL语句:Ⅰ. SELECT sname FROM s, sc WHERE grade<;60Ⅱ. SELECT sname FROM s WHERE sno IN(SELECT sno FROM sc WHERE grade<;60)Ⅲ. SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade<;60若要查找分数(grade)不及格的学生姓名(sname),则以上正确的有哪些?() A: Ⅰ和Ⅱ B: Ⅰ和Ⅲ C: Ⅱ和Ⅲ D: Ⅰ、Ⅱ和Ⅲ