Decode comma separated IDs to names

   We are on Postgres 9.6
I have a table Customer that has these fields:

ID          Rel_Id
10            12, 23, 34

Then there is this Relation table, that has this structure

Rel_id           Rel_name
12                  Mike
23                  Dave
34                  Jim

I want to show the output as:
ID           Rel_ID                       Rel_Name
10       12,23,34                      Mike, Dave, Jim

Can someone please help?
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pvsbandiAuthor Commented:
To add, the Rel_Id field in the Customer table is varchar(255) field
pvsbandiAuthor Commented:
Nevermind, I got it.

   First i have used Unnest(String_to_Array(Rel_ID,','))  AS Rel_ID FROM Customer, to turn comma separated values to rows
Then, i have joined this to the Relation table on Rel_ID and did a STRING_AGG on Relation.Rel_Name.
pvsbandiAuthor Commented:
I add my comments in the prior comments section on how i got the solution.

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