Select data in tables by conditions between 2 tables which is not linked - sql

Question

I have a large select with a lot of inner joins.
In the select I have an array_agg function for one set of data.
This array contains only a column of a table, but now I want to append at the end of the array data from another table. The data I need to add is not directly linked with the previous table where I need the column.
Query example:
select
origin_table.x,
origin_table.y,
array_agg(table1.data) ...
from
origin_table
inner join ... inner join ... full join table1 on
table.origin_table_id = origin_table.id ...
group by
...
Result array:
ID 1: example_data, {baba, bobo}
ID 2: example_data, {bibi, bubu}
Example of my tables:
table 1:
id | data | origin_table_id
----+---------+----------
1 | baba | 1
2 | bobo | 1
3 | bibi | 2
4 | bubu | 2
table 2:
id | data_bis
---+---------
1 | byby
2 | bebe
origin table:
id | table2_id
---+----------
1 | 2
2 | 1
Expected result with the 3 tables:
ID 1: example_data, {baba, bobo, bebe}
ID 2: example_data, {bibi, bubu, byby}
But got :
ID 1: example_data, {baba, bobo, bebe, byby}
ID 2: example_data, {bibi, bubu, bebe, byby}
What I need is:
How to have all the data of table 1 which respect the condition and append to it the unique table 2 data but not all elements of the table.

Answer 1

Try below query..
create table tab1 (id integer,data character varying,origin_table_id integer);
insert into tab1
select 1,'baba',1
union all
select 2,'bobo',1
union all
select 3,'bibi',2
union all
select 4,'bubu',2
create table tab2 (id integer,data_bis character varying);
insert into tab2
select 1,'byby'
union all
select 2,'bebe'
create table OriginalTable (id integer,table2_id integer);
insert into OriginalTable
select 1,2
union all
select 2,1
select * from OriginalTable
select origin_table_id,data
from tab1
union all
select OriginalTable.table2_id,data_bis
from OriginalTable
join tab2 on tab2.id = OriginalTable.id
order by origin_table_id
Result:
1;"baba"
1;"bobo"
1;"bebe"
2;"bibi"
2;"bubu"
2;"byby"

Answer 2

I can give you some idea and sample code to achieve your requirement.
First you can UNION ALL table 'table 1' and 'table 2' using the relation table 'origin table'.
WITH CTE
AS
(
SELECT AA.id,AA.data_bis,AA.origin_table_id
FROM table_1 AA
UNION ALL
SELECT NULL id, A.data_bis,B.id origin_table_id
FROM table_2 A
INNER JOIN origin_table B
ON A.id = B.table2_id
)
SELECT * FROM CTE
After applying UNION ALL, data will be looks like below-
data_bis origin_table_id
baba 1
bobo 1
bibi 2
bubu 2
byby 2
bebe 1
Now you can apply 'string_agg' on your data as below-
SELECT origin_table_id,string_agg(DISTINCT data_bis,',')
FROM CTE
GROUP BY origin_table_id
And the output will be-
origin_table_id string_agg
1 baba,bebe,bobo
2 bibi,bubu,byby
Now, you can apply further JOINING to this data as per your requirement. You can check DEMO HERE
Please keep in mind hat this is not exact solution of your issue. Just idea...