Question

我目前正致力于构建一个监控服务器上数据处理的软件。我一直在尝试构建一个查询，该查询可以确定给定系统的“当前处理日期”是什么。我试图通过首先确定最老的失败是什么来实现这一点，然后在那之前抓住日期。

我遇到的问题是我的子查询（引用已加入的其他表之一的别名）似乎在WHERE子句中传递了错误的id。

这是我写的查询：

select
    t.team_name as team,
    c.client_name as client,
    c.client_id as cid,
    p.pvl_name as pvl,
    p.pvl_id as pid,
    f.feeder as feeder,
    coalesce((
        select to_char( to_timestamp(status_date)::timestamp, 'mm/dd/yyyy' )
        from database1.status
        where
            status_date < (
                select status_date
                from database1.status
                where
                    status_date not in (
                        select status_date
                        from database1.status
                        where
                            process_step_id = 5
                            and process_state_id = 5
                            and pvl_id = p.pvl_id
                            and status_date is not null
                        )
                    and pvl_id = p.pvl_id
                order by status_date
                limit 1
                )
            and pvl_id = p.pvl_id
        limit 1
        ), '--------------' ) as through_date
from
    database1.client c
    join
    database1.pvl p on c.client_id = p.client_id
    left join (
        select child_pvl_id, count(child_pvl_id) as feeder
        from database1.relation
        group by child_pvl_id
    ) f on f.child_pvl_id = p.pvl_id
    join
    database1.team t on c.team_id = t.team_id
where c.team_id = 1
order by c.client_name, f.feeder desc

对于第一个系统，即使正确的日期应为2013年3月21日，它始终会返回'via_date'作为03/16/2013。我试图拉出子查询并用实际的pvl_id替换'p.pvl_id'，并且它正常工作，当它在使用'p.pvl_id'的子查询中时似乎只是错误地运行

Answer 1

我找到了一个问题来源。在此部分中，您设置了限制但不设置顺序。所以它可以返回任何一行：

    and pvl_id = p.pvl_id
limit 1
), '--------------' ) as through_date

我还简化了一下查询：

select
    t.team_name as team,
    c.client_name as client,
    c.client_id as cid,
    p.pvl_name as pvl,
    p.pvl_id as pid,
    f.feeder as feeder,
    coalesce((
        select to_char(to_timestamp(max(status_date))::timestamp, 'MM/DD/YYYY')
        from database1.status
        where
            status_date < (
                select min(status_date)
                from database1.status
                where
                    not (
                            process_step_id = 5
                            and process_state_id = 5
                            and pvl_id = p.pvl_id
                            and status_date is not null
                        )
                    and pvl_id = p.pvl_id
                )
            and pvl_id = p.pvl_id
        ), '--------------' ) as through_date
from
    database1.client c
    join
    database1.pvl p on c.client_id = p.client_id
    left join (
        select child_pvl_id, count(child_pvl_id) as feeder
        from database1.relation
        group by child_pvl_id
    ) f on f.child_pvl_id = p.pvl_id
    join
    database1.team t on c.team_id = t.team_id
where c.team_id = 1
order by c.client_name, f.feeder desc

别名在子查询中传递错误数据

1 个答案: