mysql提示:Illegal mix of collations for operation ‘UNION’

在保存或查询数据时提示Illegal mix of collations (gbk_chinese_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation \'=\',这里是告诉你你要保存的数据与数据库中的字符编码不致导致数据无法正确保存了,解决办法我们只要统一编码即可.

语句很简单,代码如下:

1. <?php 
2. $connection=mysql_connect("localhost","root","password"); //连接并选择数据库服务器 
3. mysql_select_db("test",$connection); 
4. $query="select * from users where name='你好'"; 
5. $result=mysql_query($query,$connection); 
6. while($row=mysql_fetch_array($result)) 
7. { //phpfensi.com 
8. echo "用户ID：".$row[0]."<br>"; //也可以写做$row["user_id"] 
9. echo "用户名：".$row[1]."<br>"; //也可以写做$row["user_name"] 
10. } 
11. ?> 

运行结果提示:Error: Illegal mix of collations (gbk_chinese_ci,IMPLICIT) and (latin1_swedish_ci,COERCIBLE) for operation '='

意思是说,操作符“=”比较的字符集不一致,一个是gbk_chinese_ci,一个是latin1_swedish_ci.

首先,查看mysql的my.cnf,确认为utf8,代码如下:

1. mysql> show variables like "%char%"; 
2. +--------------------------+-------------------------------------+ 
3. | Variable_name            | Value                               | 
4. +--------------------------+-------------------------------------+ 
5. | character_set_client     | utf8                                | 
6. | character_set_connection | utf8                                | 
7. | character_set_database   | latin1                              | 
8. | character_set_filesystem | binary                              | 
9. | character_set_results    | utf8                                | 
10. | character_set_server     | utf8                                | 
11. | character_set_system     | utf8                                | 
12. | character_sets_dir       | D:/MySQL Server 5.0/share/charsets/ | 
13. +--------------------------+-------------------------------------+ 
14. 8 rows in set (0.00 sec) 
15.  
16. mysql> show variables like "%coll%"; 
17. +----------------------+-------------------+ 
18. | Variable_name        | Value             | 
19. +----------------------+-------------------+ 
20. | collation_connection | utf8_general_ci   | 
21. | collation_database   | latin1_swedish_ci | 
22. | collation_server     | utf8_general_ci   | 
23. +----------------------+-------------------+ 
24. 3 rows in set (0.00 sec)

然后将数据库中所有编码方式改为统一,代码如下:

mysql> set character_set_database=utf8;

Query OK, 0 rows affected (0.00 sec)

mysql> set collation_database= utf8_general_ci

重新查看字符集及数据表字段编码字符是否一致.

总结:

utf8_bin

utf8_general_ci

utf8_unicode_ci

utf8_bin 与 utf8_general_ci 可以

utf8_bin 与 utf8_unicode_ci 可以

utf8_general_ci 与 utf8_unicode_ci 不可以