Dynamic alternative to pivot with CASE and GROUP BY

Question

I have a table that looks like this:

id    feh    bar
1     10     A
2     20     A
3      3     B
4      4     B
5      5     C
6      6     D
7      7              


        

Answer 1

In your case I guess an array is good. SQL Fiddle

select
    bar,
    feh || array_fill(null::int, array[c - array_length(feh, 1)]) feh
from
    (
        select bar, array_agg(feh) feh
        from foo
        group by bar
    ) s
    cross join (
        select count(*)::int c
        from foo
        group by bar
        order by c desc limit 1
    ) c(c)
;
 bar |      feh      
-----+---------------
 A   | {10,20,NULL}
 B   | {3,4,NULL}
 C   | {5,NULL,NULL}
 D   | {6,7,8}