九、as重命名

as：对字段重命名,查询结果重命名，源数据没变。

mysql> select sex as '性别' from t6 where age not in(24 , 18);
+--------+
| 性别   |
+--------+
| 男     |
| 男     |
| 男     |
| 男     |
+--------+

mysql> desc t6;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| name  | char(4) | YES  |     | NULL    |       |
| sex   | char(1) | YES  |     | NULL    |       |
| age   | int     | YES  |     | NULL    |       |
+-------+---------+------+-----+---------+-------+