如何从子查询中消除外部引用

Question

我有一个查询：

SELECT DISTINCT A2P.p_year [Year], A2P.aid [CoAuthor] 
FROM sub_aminer_author2paper A2P
WHERE pid IN (
               SELECT A2P.pid 
               FROM sub_aminer_author2paper A2P
               JOIN sub_aminer_paper P ON A2P.pid = P.pid
               WHERE DATALENGTH(P.p_abstract) > 0 AND
               A2P.aid IN (
                            SELECT aid 
                            FROM Authors
                          ) AND A2P.p_year BETWEEN 2005 AND 2014
             )
AND A2P.aid NOT IN (
                     SELECT aid 
                     FROM Authors
                   )
ORDER BY Year, CoAuthor

这个查询给我的输出是：

Year    CoAuthor
2005    796
2005    947
2005    1032
2005    1740
2005    1960
2005    4045
2005    4472 
...  
...

而我希望输出为：

Author   Year   CoAuthor   Venue
677      2005   796        234565
677      2005   947        127634
677      2005   1032       235487
1359     2005   1740       341265
1359     2005   1960       23658
1359     2005   4045       3412
1359     2005   4472       235473
...  
...

我手动添加的列是来自部分查询的 aid，即 SELECT aid FROM Authors。如何选择？而我也在使用 A2P.aid NOT IN (SELECT aid FROM Authors)，因为我不想在 CoAuthor 列中显示 Author。

Answer 1

所以您只想列出每年的所有作者/合著者团队。当从 sub_aminer_author2paper selecting 时，您已经拥有所有作者和合著者，但您必须确定谁是谁以及谁与谁一起工作。为此，请使用 cte（WITH 子句）和 select 两次：

with a2p as
(
  select 
    aid, pid, p_year, 
    case when aid in (select aid from authors) then 'author' else 'co-author' end as what
  from sub_aminer_author2paper
  where p_year between 2005 and 2014
  and pid in (select pid from sub_aminer_paper where datalength(p_abstract) > 0)
)
select distinct a.aid as [Author], a.p_year as [Year], c.aid as [CoAuthor] 
from (select * from a2p where what = 'author') a
join (select * from a2p where what = 'co-author') c on c.pid = a.pid
order by ...;

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