mysql：Illegal mix of collations错误

错误信息

Illegal mix of collations (gb2312_chinese_ci,IMPLICIT) and (latin1_swedish_ci,COERCIBLE) for operation '='//错误信息：字段字符集编码不同，不合法的连接

1. show full columns from user;命令查看tenant表各个字段的字符编码
2. alter table user convert to character set utf8;转换整个表的字段为utf8编码
3. ALTER TABLE user CHANGE username username VARCHAR( 32) CHARACTER SET gb2312 COLLATE gb2312_bin NOT NULL 命令修改user表中的username字段的字符编码为gb2312类型。保证与整个数据库的字符编码gb2312一致。