fix 乐团分班

mec-biz/src/main/resources/config/mybatis/StudentRegistrationMapper.xml

@@ -214,12 +214,6 @@
     </select>
 
     <update id="updateByUserIdAndMusicGroupId" parameterType="com.ym.mec.biz.dal.entity.StudentRegistration">
-        UPDATE student_registration
-        <set>
-            <if test="classGroupId != null != null">
-                class_group_id_ = #{classGroupId},
-            </if>
-        </set>
-        WHERE user_id_ = #{userId} AND music_group_id_ = #{musicGroupId}
+        UPDATE student_registration SET class_group_id_ = #{classGroupId} WHERE user_id_ = #{userId} AND music_group_id_ = #{musicGroupId}
     </update>
 </mapper>