ID  primarykey  Constant    BeginDate   EndDate
1   201922893   324        2018/12/01   2019/04/30
1   204225217   338        2019/05/01   NULL
2   200562823   411        2018/12/01   2019/03/31
2   202525490   461        2019/04/01   2019/04/30
2   204228089   461        2019/05/01   NULL
3   201812073   353        2019/03/01   2019/03/31
3   204231024   353        2019/05/01   NULL

ID  Date        Constant
1   2019/03/01  324
1   2019/04/01  324
1   2019/05/01  338
2   2019/03/01  411
2   2019/04/01  461
2   2019/05/01  461
3   2019/03/01  353
3   2019/04/01  Null
3   2019/05/01  353