SQL 将课程号为‘002’的授课老师改为‘张三’

Student(Sno,Sname,Sage,Ssex) 学生表 Sno：学号；Sname：姓名；Sage：年龄；Ssex：性别
Course(Cno,Cname,Tno) 课程表 Cno,课程编号；Cname：课程名字；Tno：教师编号
SC(Sno,Cno,score) 成绩表 Sno：学号；Cno,课程编号；score：成绩
Teacher(Tno,Tname) 教师表 Tno：教师编号； Tname：教师名字

怎么写

update teacher set tname="张三" where tno=(select distinct tno from course where cno="002")

 update Course set Tno = select TName from Teacher where Tname='张三') where  Cno='002'

update teacher set tname="张三" where tno = (select distinct tno from course where tno="002")