mysql数据库操作之通过as给字段取别名
案例运行代码：
- mysql> select '锄禾日当午' as '标题'; -- 取别名
- +------------+
- | 标题 |
- +------------+
- | 锄禾日当午 |
- +------------+
- 1 row in set (0.00 sec)
- mysql> select ch,math,ch+math as '总分' from stu;
- +------+------+------+
- | ch | math | 总分 |
- +------+------+------+
- | 80 | NULL | NULL |
- | 77 | 76 | 153 |
- | 55 | 82 | 137 |
- | NULL | 74 | NULL |
- -- 多学一招：as可以省略
- mysql> select ch,math,ch+math '总分' from stu;
- +------+------+------+
- | ch | math | 总分 |
- +------+------+------+
- | 80 | NULL | NULL |
- | 77 | 76 | 153 |
- | 55 | 82 | 137 |
- | NULL | 74 | NULL |
|
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