1.select count(*) from Teacher where Tname like "李%"
2.select S#,Sname from Student where S# NOT IN(select S# from SC where C# = (select C# from Course where T# = (select T# from Teacher where Tname = '叶平')))
3.select S# , Sname from Student where S# in (select S# from SC where C# = "001" )
1、SELECT COUNT(*) AS 李老师个数 FROM teacher WHERE teacher.Tname LIKE '李%'; 2、SELECT student.`S#` as 学号, student.Sname as 姓名 FROM student WHERE student.`S#` NOT IN ( SELECT sc.`S#` FROM course, teacher, sc WHERE sc.`C#` = course.`C#` AND course.`T#` = teacher.`T#` AND teacher.Tname = '叶平'); 3、SELECT student.`S#` as 学号, student.Sname as 姓名 FROM student WHERE student.`S#` in (SELECT sc.`S#` FROM sc, course WHERE sc.`C#` = course.`C#` AND course.`C#` = 1 AND student.`S#` IN (SELECT sc.`S#` FROM sc as scores WHERE scores.`C#` = 2) );
1. select count(*) from Teacher where Tname like '李%';
2. select S#, Sname from Student where S# not in (select distinct (SC.S#) from Teacher, SC, Course where SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = "叶平");
3. select Student.S#, Student.Sname from Student, SC where Student.S# = SC.S# and SC.C# = "001" and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002' )
1.select count(*) from Teacher where Tname like "李%";
2.select S#,Sname from Student where S# not in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='叶平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='叶平'));
3.select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# and SC.C#='001'and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002');