一、错误描述

org.springframework.jdbc.UncategorizedSQLException: 
### Error querying database.  Cause: java.sql.SQLException: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation =
### The error may exist in com/herin/api/modules/rockpressure/mapper/mysql/KyWzPowerMapper.java (best guess)
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: SELECT  id,area_name,value,create_time  FROM ky_wz_power     WHERE (area_name = ?) AND create_time >=(DATE_FORMAT( NOW(), %Y-%m-%d ) - INTERVAL 7 DAY)
### Cause: java.sql.SQLException: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation =
; uncategorized SQLException; SQL state [HY000]; error code [1267]; Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation =; nested exception is java.sql.SQLException: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation =
	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:92)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441)
	at com.sun.proxy.$Proxy96.selectList(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:224)

Cause: java.sql.SQLException: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation ‘=’

二、解决方案

改变数据库表的字符集

ALTER TABLE `ky_wz_power` CONVERT TO CHARACTER SET utf8;