这里的"*"是一个通配符，它表示任意匹配，如果你学过基本的正则表达式，这应该比较好理解，所以"*"放在列的位置，表示的是要查询所有列的数据；我们是查询network3这张表中的全部列的数据。
（2）查询表中特定列的数据
操作如下：
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mysql> select id,name from network3; +------------+--------+ | id | name | +------------+--------+ | 3114006440 | Xuan | | 3114006441 | xpleaf | | 3114006442 | Jim | | 3114006443 | Pei | | 3214006336 | Ting | +------------+--------+ 5 rows in set (0.00 sec)
这里我们只查询了表network3中两列的内容，如果还想查询其它列的，像上面的操作那样，在列名称的位置用逗号","隔开就可以了。
（3）按特定条件查询表中的数据
有时我们可能只想要得到某个人或者相同性别的数据，这时候我们就需要指定条件来进行查询了，基本的命令语法如下：
select 列名称 from 数据库表名 where 查询条件;
看我下面的操作：
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mysql> select * from network3 where name='xpleaf'; +------------+--------+------+-----+----------+ | id | name | sex | age | address | +------------+--------+------+-----+----------+ | 3114006441 | xpleaf | male | 35 | QingYuan | +------------+--------+------+-----+----------+ 1 row in set (0.02 sec) mysql> select * from network3 where sex='female'; +------------+------+--------+-----+----------+ | id | name | sex | age | address | +------------+------+--------+-----+----------+ | 3214006336 | Ting | female | 30 | ChaoShan | +------------+------+--------+-----+----------+ 1 row in set (0.00 sec) mysql> select * from network3 where sex='male' and address='QingYuan'; +------------+--------+------+-----+----------+ | id | name | sex | age | address | +------------+--------+------+-----+----------+ | 3114006441 | xpleaf | male | 35 | QingYuan | +------------+--------+------+-----+----------+ 1 row in set (0.00 sec) mysql> select * from network3 where age > 40; +------------+------+------+-----+---------+ | id | name | sex | age | address | +------------+------+------+-----+---------+ | 3114006443 | Pei | male | 41 | PuNing | +------------+------+------+-----+---------+ 1 row in set (0.00 sec) mysql> select * from network3 where age < 40 and age >= 31; +------------+--------+------+-----+----------+ | id | name | sex | age | address | +------------+--------+------+-----+----------+ | 3114006440 | Xuan | male | 36 | ShanWei | | 3114006441 | xpleaf | male | 35 | QingYuan | | 3114006442 | Jim | male | 38 | JiangMen | +------------+--------+------+-----+----------+ 3 rows in set (0.01 sec) mysql> select * from network3 where name like "%leaf"; +------------+--------+------+-----+----------+ | id | name | sex | age | address | +------------+--------+------+-----+----------+ | 3114006441 | xpleaf | male | 35 | QingYuan | +------------+--------+------+-----+----------+ 1 row in set (0.00 sec)