(6) selects.s_no,s.s_name,co.course_no,co.course_namefromChoicec,Students,Courseco
wherec.score=0 andc.s_no=s.s_noandco.course_no=c.course_no;
(7) selectst.s_no,st.s_name,co.course_no,co.course_name,co.course_score
fromChoicec,Courseco,Studentst
wherec.score<60 andc.s_no=st.s_noandco.course_no=c.course_no;
(8) selectst.s_name,c.scorefromChoicec,Courseco,Studentstwhere
st.s_no=c.s_noandco.course_no=c.course_noandco.course_name='程序设计语言';
(9)
selectst.s_no,st.s_name,c.class_name,co.course_no,co.course_name,ch.scorefromStudentst,Classc,Choicech,Courseco
Wherec.class_no=st.class_noandc.class_dept='计算机系'andch.s_no=st.s_noandco.course_no=ch.course_no;
(10) selectte.t_name,co.course_namefromTeachingt,Teacherte,Courseco
wheret.t_no=te.t_noandco.course_no=t.couse_no;
(11) selectt_no,t_name,t_birthday
fromTeacher
wheret_birthdaybetween'1970-1-1'and'1970-12-12'
(12) selectcourse_no,count(*)人数
fromChoice groupbycourse_no;
(13) select*
from (selectt_no,count(*)c fromTeaching groupbyt_no)cc wherecc.c>=2
(14) selectavg(score)as平均成绩,max(score)as最高分,min(score)as最低分
fromChoice
wherecourse_no='01001'
(15) selectt_name,t_birthday
fromTeacher
where (t_birthday>1960)and(t_title='讲师') orderbyt_birthdaydesc
3.复杂的数据查询
（1）selectstudent.s_no,s_name,course_no,score
fromStudent
leftouterjoinChoice onStudent.s_no=Choice.s_no
（2）selects_name,Course.course_name,score
intonew_table
fromStudent,Choice,Course
whereCourse.course_no=Choice.course_no