以下（）SQL语句可以查询出课程名中只包含“_design”字符串的课程信息。
A. select * from course where cname like '%_design%'
B. select * from course where cname like '%\_design%' escape '\'
C. select * from course where cname like '%
D. _design%' escape '
E. '
F. select * from course where cname like '%*_design%' escape '*'
针对学生表Student(Sno,Sname, Ssex,Sage,Sdept)，其中sno为学号，sname为姓名，ssex为性别，sage为年龄，sdept为系别。要检索学生表中年龄在16至30岁之间（包括16和30）的学生的姓名及年龄，SQL语句正确的是（）。
A. Select * From Student Where Sage between 16 and 30
B. Select Sname, Sage From Student Where Sage between 16 and 30
C. Select Sname, Sage From Student Where Sage >= 16 and Sage<= 30
D. Select Sname, Sage From Student Where Sage >= 16 or Sage<= 30
针对学生选课表sc（sno, cno, grade），其中sno为学号，cno为课程号，grade为成绩。以下（）语句可查询选修了两门以上成绩在90分以上课程的学生学号。
A. select snofrom scwhere grade>90group by snohaving count(cno)>2
B. select snofrom scwhere grade>90group by snohaving count(*)>2
C. select snofrom scwhere grade>90 and count(*)>2group by sno
D. select snofrom scwhere grade>90group by snohaving count(distinct sno)>2
以下（）操作实现了student表与sc之间的自然连接。
A. select student.* , sc.* from student , sc where student.sno=sc.sno
B. select student.* , cno, grade 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 join sc on student.sno=sc.sno
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