Oracle 23c

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create table t1 (client_id int, transmission_id varchar2(4), timestamp timestamp, column_a varchar2(10));
create table t2 (client_id int, transmission_id varchar2(4), timestamp timestamp, column_b varchar2(10));
create table t3 (client_id int, transmission_id varchar2(4), timestamp timestamp, column_c varchar2(10));
begin
  insert into t1 (client_id, transmission_id, timestamp, column_a) values (1, 'AAA1', timestamp '2024-10-16 10:31:27', 'Banana');
  insert into t1 (client_id, transmission_id, timestamp, column_a) values (2, 'AAA2', timestamp '2024-10-16 11:31:27', 'Citrus');
  insert into t1 (client_id, transmission_id, timestamp, column_a) values (3, 'BBB1', timestamp '2024-10-16 09:12:14', 'Apple');
  insert into t2 (client_id, transmission_id, timestamp, column_b) values (1, 'AAA1', timestamp '2024-10-16 10:41:27', 'Paris');
  insert into t2 (client_id, transmission_id, timestamp, column_b) values (2, 'AAA2', timestamp '2024-10-16 11:41:27', 'London');
  insert into t2 (client_id, transmission_id, timestamp, column_b) values (3, 'BBB1', timestamp '2024-10-16 09:22:14', 'NY');
  insert into t3 (client_id, transmission_id, timestamp, column_c) values (1, 'AAA1', timestamp '2024-10-16 10:31:27', 'Eat');
  insert into t3 (client_id, transmission_id, timestamp, column_c) values (2, 'AAA2', timestamp '2024-10-16 11:31:27', 'Pry');
  insert into t3 (client_id, transmission_id, timestamp, column_c) values (3, 'BBB1', timestamp '2024-10-16 09:12:14', 'Love');
end;
/
1 rows affected

select *
from t1
full outer join t2 using (client_id, transmission_id, timestamp)
full outer join t3 using (client_id, transmission_id, timestamp)
order by client_id, transmission_id, timestamp;


CLIENT_ID
TRANSMISSION_ID
TIMESTAMP
COLUMN_A
COLUMN_B
COLUMN_C


1
AAA1
16-OCT-24 10.31.27.000000
Banana
null
Eat

1
AAA1
16-OCT-24 10.41.27.000000
null
Paris
null

2
AAA2
16-OCT-24 11.31.27.000000
Citrus
null
Pry

2
AAA2
16-OCT-24 11.41.27.000000
null
London
null

3
BBB1
16-OCT-24 09.12.14.000000
Apple
null
Love

3
BBB1
16-OCT-24 09.22.14.000000
null
NY
null

CLIENT_ID	TRANSMISSION_ID	TIMESTAMP	COLUMN_A	COLUMN_B	COLUMN_C
1	AAA1	16-OCT-24 10.31.27.000000	Banana	null	Eat
1	AAA1	16-OCT-24 10.41.27.000000	null	Paris	null
2	AAA2	16-OCT-24 11.31.27.000000	Citrus	null	Pry
2	AAA2	16-OCT-24 11.41.27.000000	null	London	null
3	BBB1	16-OCT-24 09.12.14.000000	Apple	null	Love
3	BBB1	16-OCT-24 09.22.14.000000	null	NY	null