За вашата рекурсивна заявка можете да създадете йерархичен път, като използвате този трик с подплатени низове с 0:SQL Fiddle
with recursive comment_list(article_comment_id, parent_comment_id, comment, article_id, comment_depth, comment_path) AS (
select c.article_comment_id,
c.parent_comment_id,
c.comment,
c.article_id,
c.comment_depth,
substr(CAST(1000000000+c.article_comment_id as varchar(1000)),2)
from test_comment c
where article_id = 100
and parent_comment_id = 0
union all
select c.article_comment_id,
c.parent_comment_id,
c.comment,
c.article_id,
c.comment_depth,
cl.comment_path || substr(CAST(1000000000+c.article_comment_id as varchar(1000)),2)
from test_comment c
join comment_list cl on c.parent_comment_id = cl.article_comment_id
)
select cl.article_comment_id,
cl.comment_path,
cl.parent_comment_id,
cl.comment,
cl.article_id,
cl.comment_depth
from comment_list cl
order by cl.comment_path, cl.article_comment_id, cl.comment_depth;
Пуснете GROUP BY. Искате да ги „групирате“ за показване, което всъщност е „ПОРЪЧАЙТЕ ПО“
select cl.parent_comment_id,
cl.article_comment_id,
cl.comment,
cl.article_id,
cl.comment_depth
from comment_list cl
order by cl.parent_comment_id, cl.article_comment_id, cl.comment_depth;
Може да имате нужда от cl.root_id
, а може и да не в реда по, така че може да бъде
order by cl.root_id, cl.parent_comment_id, cl.article_comment_id, cl.comment_depth;