sql - 如何在postgres中选择一列？

Question

我的查询:

select c.id, sum(case when r.paid_out>='1' then 0 else 1 end) as all_paids
from people p1, houses h, policies p2, receipts r
where p1.id = h.id
and h.code = p2.code
and p2.code_policy = r.code_policy
group by p1.id
having all_paids= 0;

Postesql 返回以下错误:

错误:没有“all_paids”列

我试过很多东西，但没有任何帮助，感谢您的帮助

Answer 1

首先，学习使用正确的 join 语法。

其次，您可以为 having 子句或子查询使用表达式:

select p1.id
from people p1 join
     houses h
     on p1.id = h.id join
     policies p2
     on h.code = p2.code join
     receipts r
     on p2.code_policy = r.code_policy
group by p1.id
having sum(case when r.paid_out >= '1' then 0 else 1 end) = 0;

注意:没有定义c.id，所以我假设select应该是p1.id基于分组依据。

我应该说这个逻辑通常会用not exists来表达:

select p1.*
from people p1
where not exists (select 1
                  from houses h
                       policies p2
                       on h.code = p2.code join
                       receipts r
                       on p2.code_policy = r.code_policy
                  where p1.id = h.id and
                        r.paid_out >= '1'
                 );

这消除了聚合。