mysql group by

<pre name="code" class="sql">mysql> select * from t2;+------+----------+------+| name | address  | flag |+------+----------+------+| a    | aaaaaaaa | 1    || a    | bbbbbb   | 1    || b    | bbbbbb   | 1    || b    | bbbbbb   | 2    || b    | bbbbbb   | 2    || a    | wwwwwww  | 2    || c    | wwwwwww  | 2    |+------+----------+------+7 rows in set (0.00 sec)mysql> select name,address from t2 group by name;+------+----------+| name | address  |+------+----------+| a    | aaaaaaaa || b    | bbbbbb   || c    | wwwwwww  |+------+----------+3 rows in set (0.00 sec)mysql> select * from t2 group by name;+------+----------+------+| name | address  | flag |+------+----------+------+| a    | aaaaaaaa | 1    || b    | bbbbbb   | 1    || c    | wwwwwww  | 2    |+------+----------+------+3 rows in set (0.00 sec)