title: MyBatis select by id always returns zero
body: <p>With the following configuration:</p>
  
  <p>POJO:</p>
  
  <pre><code>public class Student {
      private int studentId;
      private String name;
      private String email;
      // getters and setters
  }
  </code></pre>
  
  <p>StudentMapper.xml</p>
  
  <pre><code>...
  &lt;select id="findStudentById" parameterType="int" resultType="Student"&gt;
    SELECT student_id, name, email FROM Student WHERE studentId = #{studentId}
  &lt;/select&gt;
  ...
  </code></pre>
  
  <p>StudentMapper interface</p>
  
  <pre><code>public interface StudentMapper {
      ...
      Student findStudentById(int studentId);
      ...
  }
  </code></pre>
  
  <p>The problem is whenever I run <code>StudentService.findStudentById(studentId)</code> (<em>I did not put it here</em>) I got the <strong>same number (zero)</strong> every time (student_id in my table is auto_generated and started from 1 not 0) </p>
  
  <p><strong>EDIT</strong>: but other params (name and email) is returned properly</p>