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  • MySQL别名的使用

    mysql> create table student(age int(4), name varchar(20));
    Query OK, 0 rows affected (0.09 sec)

    mysql> insert into student values(21, 'Jack'), (23, 'Rose'), (35, 'Ann'), (56, 'Mike');
    Query OK, 4 rows affected (0.06 sec)
    Records: 4  Duplicates: 0  Warnings: 0

    mysql> select * from student;
    +------+------+
    | age  | name |
    +------+------+
    |   21 | Jack |
    |   23 | Rose |
    |   35 | Ann  |
    |   56 | Mike |
    +------+------+
    4 rows in set (0.00 sec)

    (1)为表取别名

    mysql> select * from student s where age > 30;
    +------+------+
    | age  | name |
    +------+------+
    |   35 | Ann  |
    |   56 | Mike |
    +------+------+
    2 rows in set (0.00 sec)
    
    mysql>

    (2)为字段取别名

    mysql> select age as student_age, name as student_name from student;
    +-------------+--------------+
    | student_age | student_name |
    +-------------+--------------+
    |          21 | Jack         |
    |          23 | Rose         |
    |          35 | Ann          |
    |          56 | Mike         |
    +-------------+--------------+
    4 rows in set (0.00 sec)
    
    mysql>
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  • 原文地址:https://www.cnblogs.com/Robotke1/p/3058980.html
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