MySQL 8.0

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create table test (
FLOW integer,
OTPERIOD char(7),
LOG_DATE date,
LOG_TIME time,
ENTITY integer
);
insert into test values( '1000', '2016.12', '2017-08-31', '17:12:18', '1059' );	
insert into test values( '1000', '2016.12', '2017-08-30', '17:06:53', '1059' );	
insert into test values( '1000', '2016.12', '2017-08-30', '17:05:58', '1059' );
insert into test values( '1000', '2016.12', '2017-09-17', '13:11:39', '2215' );	
insert into test values( '1000', '2016.12', '2017-09-16', '13:09:57', '2215' );	
insert into test values( '1000', '2016.12', '2017-09-16', '12:03:26', '2215' );
insert into test values( '1000', '2016.12', '2017-08-23', '19:17:18', '8998' );	
insert into test values( '1000', '2016.12', '2017-08-22', '19:14:32', '8998' );	
insert into test values( '1000', '2016.12', '2017-08-22', '17:00:08', '8998' );
select * from test;


FLOW
OTPERIOD
LOG_DATE
LOG_TIME
ENTITY


1000
2016.12
2017-08-31
17:12:18
1059

1000
2016.12
2017-08-30
17:06:53
1059

1000
2016.12
2017-08-30
17:05:58
1059

1000
2016.12
2017-09-17
13:11:39
2215

1000
2016.12
2017-09-16
13:09:57
2215

1000
2016.12
2017-09-16
12:03:26
2215

1000
2016.12
2017-08-23
19:17:18
8998

1000
2016.12
2017-08-22
19:14:32
8998

1000
2016.12
2017-08-22
17:00:08
8998


-- For MySQL 8.0
select FLOW, OTPERIOD, LOG_DATE, LOG_TIME, ENTITY
  from (
    select
      FLOW, OTPERIOD, LOG_DATE, LOG_TIME, ENTITY,
      row_number() over (partition by ENTITY order by LOG_DATE desc, LOG_TIME desc) num
    from test
  ) tt
  where num = 1
;


FLOW
OTPERIOD
LOG_DATE
LOG_TIME
ENTITY


1000
2016.12
2017-08-31
17:12:18
1059

1000
2016.12
2017-09-17
13:11:39
2215

1000
2016.12
2017-08-23
19:17:18
8998


-- For MySQL <=8.0
select t.*
  from test t
  inner join (
    select max(LOG_DATE) LOG_DATE, MAX(LOG_TIME) LOG_TIME, ENTITY
      from test
      group by ENTITY
      having concat(LOG_DATE,' ', LOG_TIME) = max(concat(LOG_DATE,' ', LOG_TIME))
) tt on tt.ENTITY = t.ENTITY and tt.LOG_DATE = t.LOG_DATE and tt.LOG_TIME = t.LOG_TIME
;


FLOW
OTPERIOD
LOG_DATE
LOG_TIME
ENTITY


1000
2016.12
2017-08-31
17:12:18
1059

1000
2016.12
2017-09-17
13:11:39
2215

1000
2016.12
2017-08-23
19:17:18
8998


-- For MySQL <=8.0
select *
  from test t
  where concat(LOG_DATE,' ', LOG_TIME) = (
    select max(concat(LOG_DATE,' ', LOG_TIME))
      from test tt
        where tt.ENTITY = t.ENTITY
      group by ENTITY
  )
;


FLOW
OTPERIOD
LOG_DATE
LOG_TIME
ENTITY


1000
2016.12
2017-08-31
17:12:18
1059

1000
2016.12
2017-09-17
13:11:39
2215

1000
2016.12
2017-08-23
19:17:18
8998

FLOW	OTPERIOD	LOG_DATE	LOG_TIME	ENTITY
1000	2016.12	2017-08-31	17:12:18	1059
1000	2016.12	2017-08-30	17:06:53	1059
1000	2016.12	2017-08-30	17:05:58	1059
1000	2016.12	2017-09-17	13:11:39	2215
1000	2016.12	2017-09-16	13:09:57	2215
1000	2016.12	2017-09-16	12:03:26	2215
1000	2016.12	2017-08-23	19:17:18	8998
1000	2016.12	2017-08-22	19:14:32	8998
1000	2016.12	2017-08-22	17:00:08	8998