PostgreSQL array_agg命令窗口功能

Question

我的问题的答案几乎在这里： PostgreSQL array_agg order

除了我想在窗口函数上使用array_agg之外：

 select distinct c.concept_name, 
        array_agg(c2.vocabulary_id||':'||c2.concept_name 
                  order by c2.vocabulary_id, c2.concept_name) 
            over (partition by ca.min_levels_of_separation), 
        ca.min_levels_of_separation
 from concept c
 join concept_ancestor ca on c.concept_id = ca.descendant_concept_id 
      and max_levels_of_separation > 0
 join concept c2 on ca.ancestor_concept_id = c2.concept_id 
 where 
 c.concept_code = '44054006'
 order by min_levels_of_separation;

因此，也许这将在将来的某些版本中起作用，但我收到此错误

 ERROR:  aggregate ORDER BY is not implemented for window functions
 LINE 2: select distinct c.concept_name, array_agg(c2.vocabulary_id||...
                                    ^

我可能应该从子查询中进行选择，例如上述引用问题的第一个答案。 我希望有一个简单的命令（在该问题的第二个答案中）。 或者，也许我只是对查询懒惰，应该做一个group by而不是select distinct 。

我确实尝试通过窗口函数放置命令（ over (partition by ca.min_levels_of_separation order by c2.vocabulary_id, c2.concept_name) ），但是我通过这种方式得到了这种重复行：

 "Type 2 diabetes mellitus";"{"MedDRA:Diabetes mellitus"}";1
 "Type 2 diabetes mellitus";"{"MedDRA:Diabetes mellitus","MedDRA:Diabetes mellitus (incl subtypes)"}";1
 "Type 2 diabetes mellitus";"{"MedDRA:Diabetes mellitus","MedDRA:Diabetes mellitus (incl subtypes)","SNOMED:Diabetes mellitus"}";1

（顺便说一句： http : //www.ohdsi.org/如果您恰好对我从哪里获得医疗词汇表感到好奇）

Answer 1

是的，看起来我好像一头雾水，不需要窗口功能。 这似乎可行：

 select  c.concept_name, 
         array_agg(c2.vocabulary_id||':'||c2.concept_name 
                   order by c2.vocabulary_id, c2.concept_name), 
         ca.min_levels_of_separation
 from concept c
 join concept_ancestor ca on c.concept_id = ca.descendant_concept_id 
      and max_levels_of_separation > 0
 join concept c2 on ca.ancestor_concept_id = c2.concept_id
 where c.concept_code = '44054006'
 group by c.concept_name, ca.min_levels_of_separation
 order by min_levels_of_separation

我暂时不会接受我的回答，因为它只是避免了这个问题，而不是实际回答这个问题，并且有人可能会对此事说些更有用的话。

Answer 2

像这样 ：

select distinct c.concept_name, 
    array_agg(c2.vocabulary_id||':'||c2.concept_name ) over (partition by ca.min_levels_of_separation  order by c2.vocabulary_id, c2.concept_name), 
    ca.min_levels_of_separation
from concept c
join concept_ancestor ca on c.concept_id = ca.descendant_concept_id 
  and max_levels_of_separation > 0
join concept c2 on ca.ancestor_concept_id = c2.concept_id 
where 
c.concept_code = '44054006'
order by min_levels_of_separation;