如何做一个Postgresql子查询的select子句与像SQL Server一样的join子句？

我试图写下面的查询postgresql：

select name,author_id,count(1),(select count(1)
    from names as n2
    where n2.id = n1.id
        and t2.author_id = t1.author_id
    )               
from names as n1
group by name,author_id

这将肯定工作在Microsoft sql Server，但它根本不在postegresql。我读了它的文档有点，它似乎我可以重写它：

select name,total                     
from names as n1,(select count(1) as total
    from names as n2
    where n2.id = n1.id
        and n2.author_id = t1.author_id
    ) as total
group by name,author_id

但是这会在postegresql上返回以下错误：“FROM中的子查询不能引用同一查询级别的其他关系”。所以我被卡住了。有谁知道我怎么能实现呢？

谢谢

我不知道我完全理解你的意图，但也许以下将接近你想要的：

select n1.name,n1.author_id,count_1,total_count
  from (select id,name,count(1) as count_1
          from names
          group by id,author_id) n1
inner join (select id,count(1) as total_count
              from names
              group by id,author_id) n2
  on (n2.id = n1.id and n2.author_id = n1.author_id)

不幸的是，这增加了按照id以及name和author_id对第一个子查询进行分组的要求，我认为这是不需要的。我不知道如何解决，但是，因为你需要有id可用于加入第二个子查询。也许别人会想出一个更好的解决方案。

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