与查询Select student.* from student,grade Where student.sno=grade.sno and grade.score>90等价的语句是( )。
举一反三
- 查询每个学生的学号、姓名、选修的课程名及成绩，下列（)的操作是正确的。 A: select student,sno,sname,grade from student,sc where student.sno=sc.sno and sc.cno=course.cno B: select student,sno,sname,grade from student,sc,cource where student.sno=sc.sno C: select student,sno,sname,grade from student,sc,cource where sc.cno=course.cno D: select student,sno,sname,grade from student,sc,cource where student.sno=sc.sno and sc.cno=course.cno
- 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
- 【多选题】针对学生选课数据库S_T，以下()操作实现了student表与sc之间的自然连接。 A. select student.* , cno, grade from student join sc on student.sno=sc.sno B. select student.* , sc.* from student , sc where student.sno=sc.sno C. select student.sno, sname, ssex, sage, sdept , cno, grade from student , sc where student.sno=sc.sno D. select student.* , cno, grade from student , sc where student.sno=sc.sno
- 以下命令是相关子查询的嵌套查询是： A: SELECT * FROM student WHERE sno IN (SELECT sno FROM sc WHERE cno = '1') B: SELECT * FROM student WHERE EXISTS (SELECT * FROM sc WHERE cno = '1' AND sc.sno = student.sno) C: SELECT sno, cno FROM sc x WHERE grade>(SELECT AVG(grade) FROM sc y WHERE y.sno = x.sno) D: 以上都是
- 查询曾经考过100分的学生的学号，可以使用的SQL语句是：（ ） A: SELECT ALL Sno FROM SC WHERE Grade = 100; B: SELECT DISTINCT Sno FROM SC WHERE Grade = 100; C: SELECT ALL Sno FROM Student WHERE SGrade = 100; D: SELECT DISTINCT Sno FROM Student WHERE SGrade = 100;