如何从 postgresql 查询中的嵌套选择返回多列？

Question

我有一个如下所示的 postgresql 查询：

      update service_requests
      set service_request_status = 'Rejected', modified_on = now()
      where service_request_id = $1 and service_request_status = 'Submitted'
      returning 
        (select service_request_id, service_request_status, requestor_id
        from service_requests
        where service_request_job_uuid in
          (select service_request_job_uuid from service_requests where service_request_id = $1)
        )

我收到一个错误：子查询必须只返回一列

但我至少需要返回三个：service_request_id、service_request_status、requestor_id。并且它们需要从被更新的记录所属的一组记录中返回。

这个想法是这样的：用户向一个或多个我们称之为“专业人士”的“专业人士”提交服务请求。这些专业人士对服务请求进行投标。每个专业人士的数据库中都有一行，它们按 service_request_job_uuid 列分组在一起。在专业人士拒绝服务请求的情况下，将运行此查询。我们想返回该服务请求对应的所有记录，看看是否还有其他专业人士尚未拒绝该服务请求。

但是如果我在第一个嵌套选择中不能选择多个列，我该如何返回我需要的信息呢？

谢谢。

Answer 1

我想你想要：

with upd as (
    update service_requests
    set service_request_status = 'Rejected', modified_on = now()
    where service_request_id = $1 and service_request_status = 'Submitted'
    returning service_request_id 
)
select service_request_id, service_request_status, requestor_id
from service_requests sr
where exists (
    select 1 
    from service_requests sr1
    inner join upd u on u.service_request_id = sr1.service_request_id 
    where sr1.service_request_job_uuid = sr.service_request_job_uuid
)

或者，也许：

with upd as (
        update service_requests
        set service_request_status = 'Rejected', modified_on = now()
        where service_request_id = $1 and service_request_status = 'Submitted'
        returning service_request_job_uuid 
    )
select sr.service_request_id, sr.service_request_status, sr.requestor_id
from service_requests sr
inner join upd u on u.service_request_job_uuid = sr.service_request_job_uuid