SELECT * FROM class_group_student_mapper WHERE id_ = #{id} SELECT * FROM class_group_student_mapper ORDER BY id_ INSERT INTO class_group_student_mapper (id_,class_group_id_,user_id_,status_,create_time_) VALUES(#{id},#{classGroupId},#{userId},#{status},now()) UPDATE class_group_student_mapper user_id_ = #{userId}, class_group_id_ = #{classGroupId}, status_ = #{status,typeHandler=com.ym.mec.common.dal.CustomEnumTypeHandler}, WHERE id_ = #{id} DELETE FROM class_group_student_mapper WHERE id_ = #{id} SELECT * FROM class_group_student_mapper ORDER BY id_ SELECT COUNT(*) FROM class_group_student_mapper INSERT INTO class_group_student_mapper (id_,class_group_id_,user_id_,status_,create_time_) (#{item.id},#{item.classGroupId},#{item.userId},#{item.status},#{item.createTime}) SELECT * FROM class_group_student_mapper where class_group_id_ = #{classGroupId} and user_id_ = #{userId}