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  • Unknown column 't_user.id' in 'where clause'(通过字段名删除不了数据)

    创建员工信息表t_user

    CREATE TABLE t_user(

      id INT PRIMARY KEY AUTO_INCREMENT,

      username VARCHAR(20) ,

      password VARCHAR(20) ,

      age int ,

      phone VARCHAR(20) ,

      email VARCHAR(20) ,

      is_Delete int

    )DEFAULT CHARSET=UTF8;

    往员工表中插入数据:

    INSERT INTO t_user VALUES(null,'张三','123456',23,'110','11111@qq.com',1),(null,'历史','123456',23,'110','11111@qq.com',1),(null,'孙悟空','123456',23,'110','11111@qq.com',2),(null,'李白','123456',23,'110','11111@qq.com',2),(null,'八戒','123456',23,'110','11111@qq.com',2);

    问题:发现用delete from t_user where id=6;这个语句删除不了,其它字段名也试过了也不行,如下:

    mysql> select * from t_user;
    +----------+----------------+----------------+-----------+-------------+--------------+-----------------+
    |   id   |   username   |   password   |   age   |   phone   |   email    |   is_Delete   |
    +----------+----------------+----------------+-----------+-------------+--------------+-----------------+
    |        1 | 唐僧           | 123456         |        23 | 110         | 11111@qq.com |               2 |
    |        2 | 张三           | 123456         |        23 | 110         | 11111@qq.com |               1 |
    |        3 | 历史           | 123456         |        23 | 110         | 11111@qq.com |               1 |
    |        4 | 孙悟空         | 123456         |        23 | 110         | 11111@qq.com |               2 |
    |        5 | 李白           | 123456         |        23 | 110         | 11111@qq.com |               2 |
    |        6 | 八戒           | 123456         |        23 | 110         | 11111@qq.com |               2 |
    +----------+----------------+----------------+-----------+-------------+--------------+-----------------+
    6 rows in set (0.00 sec)
    
    mysql> mysql> delete from t_user where id=6;
    ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'delete from t_user where id=6' at line 1
    mysql> delete from t_user where id='6';
    ERROR 1054 (42S22): Unknown column 'id' in 'where clause'
    mysql> delete form t_user where id=6;
    ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 't_user where id=6' at line 1
    mysql> delete from t_user where id=6;
    ERROR 1054 (42S22): Unknown column 'id' in 'where clause'
    mysql> delete from t_user where username='八戒';
    ERROR 1054 (42S22): Unknown column 'username' in 'where clause'
    mysql> delete from t_user where t_user.id=6;
    ERROR 1054 (42S22): Unknown column 't_user.id' in 'where clause'
    mysql> 

    然后发现是表中的字段名有空格,正常的没空格的如下:

    mysql> select * from dept;
    +----+--------+
    | id | name   |
    +----+--------+
    |  1 | 神仙   |
    |  2 | 妖怪   |
    +----+--------+

    字段名出现空格的话,通过字段名进行数据操作的时候要给字段名添加单引号,如下:

    mysql> delete from t_user where 'id'=6;
    Query OK, 0 rows affected, 1 warning (0.07 sec)
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  • 原文地址:https://www.cnblogs.com/package-java/p/10494380.html
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