On 3/2/23 14:49, Ron wrote:
On 3/2/23 15:45, Rob Sargent wrote:
On 3/2/23 13:58, Ron wrote:
Postgresql 12.13
Given the sample below, I'm looking for how to generate this output. It's like GROUP BY, but generating an array instead of an aggreate number.
f1 | f2_array
----+---------
1 | {1,2,3}
2 | {1,2,3,4}
3 | {1,2}
The ultimate goal is to somehow use pg_index.indkey to get column names from pg_attribute.
create table foo (f1 int, f2 int);
insert into foo values (1, 1);
insert into foo values (1, 2);
[snip]
In which environment are you accessing that array? psql only?
Correct.
For multiple columns it's a litte messier ( if you have different data types in your columns)
create table foo (f1 int, f2 int, f3 text);
insert into foo values (1, 1,'asdf');
insert into foo values (1, 2, 'qerr');
select f1, array_agg(array[f2::text,f3]) from foo group by f1;
f1 | array_agg
----+---------------------
1 | {{1,asdf},{2,qerr}}
(1 row)