SELECT * FROM class_group_relation WHERE id_ = #{id} SELECT * FROM class_group_relation ORDER BY id_ INSERT INTO class_group_relation (id_,class_group_id_,sub_class_group_id_,create_time_) VALUES(#{id},#{classGroupId},#{subClassGroupId},now()) UPDATE class_group_relation sub_class_group_id_ = #{subClassGroupId}, class_group_id_ = #{classGroupId}, WHERE id_ = #{id} DELETE FROM class_group_relation WHERE id_ = #{id} DELETE FROM class_group_relation WHERE class_group_id_ = #{classGroupId} SELECT * FROM class_group_relation ORDER BY id_ SELECT COUNT(*) FROM class_group_relation INSERT INTO class_group_relation (class_group_id_,sub_class_group_id_,create_time_) VALUES (#{item.classGroupId},#{item.subClassGroupId},now()) SELECT * FROM class_group_relation WHERE sub_class_group_id_ = #{subClassGroupId} LIMIT 1 SELECT class_group_id_ 'value',sub_class_group_id_ 'key' FROM class_group_relation cgr WHERE cgr.class_group_id_ IN (SELECT cg.id_ FROM class_group cg WHERE cg.music_group_id_ = #{musicGroupId} AND cg.type_ = 'MIX') SELECT sub_class_group_id_ 'key' ,cg.name_ 'value' FROM class_group_relation cgr LEFT JOIN class_group cg ON cgr.class_group_id_ = cg.id_ WHERE cgr.class_group_id_ IN (SELECT cg.id_ FROM class_group cg WHERE cg.music_group_id_ = #{musicGroupId} AND cg.type_ = 'MIX') DELETE FROM class_group_relation WHERE sub_class_group_id_ = #{classGroupId}