java.sql.SQLException: Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation '='

查询视图时报错：java.sql.SQLException: Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation '='；

本地环境:mysql8.0.13

异常提示排序规则编码混乱，mysql8.0.1之后的默认COLLATE为utf8mb4_0900_ai_ci；

检查视图中所包含的表发现其中一个建表时没有设置编码，并且其他的表设置的是 CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci；因此导致混乱；

查看当前数据库的默认编码：

mysql> show variables where Variable_name like 'collation%';

java.sql.SQLException: Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation '='

查看各表编码：

mysql> show create table ‘table_name’;

解决方案给没有设置编码的表重新设置一下：

mysql> alter table table_name default character set utf8mb4 collate=utf8mb4_general_ci;

java.sql.SQLException: Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation '='

这样设置只针对表的，但是表中字段未修改：

mysql> ALTER TABLE table_name convert to CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

java.sql.SQLException: Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation '='

修改完成以后，重新创建视图！！！！