sql语句练习题及答案

* from course o in(‘1001’,’1002’) andР not exists(select * from sc where sno =student.sno o=o) )Рa:select top 1 sno from o=’1002’ order by grade descРb:select sno from sc o=’1002’ and grade >=all (Р select grade from sc o=’1002’)Рselect top 3 sno from sc group by sno order by avg(grade)descРa:select*from student where sdept=’JSJ’ and sage>19Рb:select*from student where sdept=’JSJ’ except select* from student where sage<19Рselect student.sno,sname from student,sc o=’1001’ and grade>90Р union select sno,sname from student where sno in (Р select sno from sc group by sno having avg(grade)>85)Рselect sno from student where sno not in(select sno from sc x where grade< (Р select avg(grade) from sc o=o) )Рselect sname from student x where sage> (Р select avg(sage) from student where sdept=x.sdept)