我正在从mysql命令行更新一个表。。更新未发生。。
表格说明如下：

mysql> describe userdailycalorie;
+-------------------+----------+------+-----+---------+-------+
| Field             | Type     | Null | Key | Default | Extra |
+-------------------+----------+------+-----+---------+-------+
| id                | int(11)  | NO   | PRI | NULL    |       |
| balanced_diet     | bit(1)   | YES  |     | NULL    |       |
| calories_consumed | double   | YES  |     | NULL    |       |
| date              | datetime | YES  |     | NULL    |       |
| user_id           | int(11)  | YES  | MUL | NULL    |       |
+-------------------+----------+------+-----+---------+-------+
5 rows in set (0.13 sec)

相应的表格内容如下：

mysql> select * from userdailycalorie;
+----+---------------+-------------------+---------------------+---------+
| id | balanced_diet | calories_consumed | date                | user_id |
+----+---------------+-------------------+---------------------+---------+
| 16 |               |                 0 | 2018-02-02 00:00:00 |       3 |
+----+---------------+-------------------+---------------------+---------+
1 row in set (0.00 sec)

相应的update语句如下：

mysql> update userdailycalorie  set calories_consumed= 205.4  and balanced_diet =true WHERE user_id = 3;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

匹配的行数为1，表示它选择了行。。更新未按更改进行：0。。我不知道为什么，。。。有人能帮我调试这个问题吗？