[c.y.j]mybatis choose when otherwise

<select id="searchCourses" parameterType="hashmap" resultMap="CourseResult"> SELECT * FROM COURSES 

<choose> 

<when test="searchBy == 'Tutor'"> WHERE TUTOR_ID= #{tutorId} </when> 

<when test="searchBy == 'CourseName'"> WHERE name like #{courseName} </when> 

<otherwise> WHERE TUTOR start_date >= now() </otherwise> 

</choose> 

</select>