where in 和where=

比如 select * from student where Sname='张三'；/*查询姓名叫张三的学生的信息*/select * from student where Sname in('张三','李四')；/*查询张三和李四的学生的信息*/select * from student where Sname in(select Sname from sn where Sno='001')；/*查询学号是001的学生信息*/