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：
原文链接：https://www.f2er.com/postgresql/193405.htmlselect 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。
分享和享受。
