retorna a coluna com maior valor

gistfile1.sql

with tabela as (
    select format('%s.%s', quote_ident(nsp.nspname), quote_ident(t.tablename)) as tablename, c.oid
    from pg_catalog.pg_tables t
    inner join pg_catalog.pg_class c on c.relname = t.tablename
    inner join pg_catalog.pg_namespace nsp on nsp.nspname = t.schemaname and nsp.oid = c.relnamespace
    where t.tablename = :tablename and nsp.nspname = :schemaname
), cols_dif_resultado as (
    select
        t.tablename, att.attname as col
    from pg_catalog.pg_attribute att
    inner join tabela t on t.oid = att.attrelid
    where att.attnum > 0 and att.attname not in ('COLUNAS', 'QUE', 'EU', 'NÃO', 'QUERO', 'CONSIDERAR')
)
select format('with aux as (
    select t.*, n.col
    from %s t, (values %s) as n(col)
), aux2 as (
    select
        id, 
        col,
        rank() over(partition by id order by 
                                        case col %s
                                        end desc
        ) n
    from aux
)

select id, col
from aux2
where n = 1', 
    c.tablename, 
    string_agg(format('(''%s'')', c.col), ','),
    string_agg(format('when ''%s'' then %s', c.col, c.col), E'\n'))
from cols_dif_resultado c
group by c.tablename;