Concatenate multiple rows in an array with SQL on PostgreSQL

Question

I have a table constructed like this :

oid | identifier | value
1   | 10         | 101
2   | 10         | 102
3   | 20         | 201
4   | 20         | 202
5         


        

Answer 1

Here is the code for the requested output.

select identifier, array_agg(value)
from (
  values
    (1   , 10         , 101),
    (2   , 10         , 102),
    (3   , 20         , 201),
    (4   , 20         , 202),
    (5   , 20         , 203)
  ) as tab (oid, identifier, value)
group by identifier
order by identifier;