我有张表stu ,表里面有id,name,age这几个字段  表如下
                      id       name       age
                      1        张三       21
                      2        张三       25
                      3        张三       23
                      4        李四       22
                      5        李四       21
                      6        李四       24
现在我想按name分类查询每个名字的前两行数据 ，结果如下
                      id       name       age
                      1        张三       21
                      2        张三       25
                      4        李四       22
                      5        李四       21
请问代码怎么写？谢谢了