MyBatis BindingException: Invalid Bound Statement (not found)

This error is thrown when MyBatis is unable to find the specified SQL statement in the mapper XML file. In this case, it is looking for the statement 'com.example.demo1.mapper.StudentMapper.selectById' but it is not able to find it in the mapper XML file.

To resolve this issue, check the mapper XML file and ensure that the statement is correctly defined and that the namespace and id match the one specified in the code. Also, make sure that the mapper interface is correctly referenced in the MyBatis configuration file.