【已解决】IDEA mybatis报错

错误信息

Cause: org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='stuclass', mode=IN, javaType=class java.lang.String, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName='null', expression='null'}. Cause: org.apache.ibatis.type.TypeException: Error setting non null for parameter #2 with JdbcType null . Try setting a different JdbcType for this parameter or a different configuration property. Cause: java.sql.SQLException: Parameter index out of range (2 > number of parameters, which is 1).
The error may exist in mapper/StudentMapper.xml
The error may involve main.resources.mapper.StudentMapper.selentAvgByClass-Inline
The error occurred while setting parameters
 SQL: -- SELECT avg(stuscore) FROM score group by stuclass having stuclass = ?         SELECT avg(stuscore) FROM score group by stuclass having stuclass = ?

解决：

原因竟然是，注释掉了一行代码，我晕，这个xml太坑了。。。

删除注释掉的代码后再次运行，不再报错：