oracle查询结果合并排序

Question

SQL_activities = "select ACTIVITIE_ID,ACTIVITIE_TITLE,ACTIVITIE_CONTENT,ACTIVITIE_RULE,"
"ACTIVITIE_RANGE,BRANCH_CODE,START_TIME,END_TIME,CITY_CODE,RECEIVE_START_TIME,RECEIVE_END_TIME,RECEIVE_ADDRESS,"
"P_NAME,(case when sysdate < START_TIME then '0' when sysdate >= START_TIME and sysdate <= RECEIVE_END_TIME then '1' end) STATUS from MP_DISCOUNT_ACTIVITIES where DELETE_FLAG = '0' and VERIFY_FLAG != '0'"
"and END_TIME >= SYSDATE order by ACTIVITIE_RANGE ASC,CITY_CODE ASC",
SQL_activities2 = "select ACTIVITIE_ID,ACTIVITIE_TITLE,ACTIVITIE_CONTENT,ACTIVITIE_RULE,"
"ACTIVITIE_RANGE,BRANCH_CODE,START_TIME2,END_TIME2,CITY_CODE,RECEIVE_START_TIME,RECEIVE_END_TIME,RECEIVE_ADDRESS," "P_NAME,(case when sysdate < START_TIME2 then '0' when sysdate >= START_TIME2 and sysdate <= RECEIVE_END_TIME then '1' end) STATUS from MP_DISCOUNT_ACTIVITIES where DELETE_FLAG = '0' and VERIFY_FLAG != '0'"
"and END_TIME2 >= SYSDATE order by ACTIVITIE_RANGE ASC,CITY_CODE ASC",
SQL_activities3 = "select ACTIVITIE_ID,ACTIVITIE_TITLE,ACTIVITIE_CONTENT,ACTIVITIE_RULE,"
"ACTIVITIE_RANGE,BRANCH_CODE,START_TIME3,END_TIME3,CITY_CODE,RECEIVE_START_TIME,RECEIVE_END_TIME,RECEIVE_ADDRESS,"
"P_NAME,(case when sysdate < START_TIME3 then '0' when sysdate >= START_TIME3 and sysdate <= RECEIVE_END_TIME then '1' end) STATUS from MP_DISCOUNT_ACTIVITIES where DELETE_FLAG = '0' and VERIFY_FLAG != '0'"
"and END_TIME3 >= SYSDATE order by ACTIVITIE_RANGE ASC,CITY_CODE ASC",
backend_db:select(SQL_activities)++backend_db:select(SQL_activities2)++backend_db:select(SQL_activities3).
查找出来的结果怎么统一排序，本来的表里就一个时间字段，现在增加了两组，急急急