Question

好的，手头的任务是

获取已分发展览的奖品总和，直至2017年8月31日，收集和照片。我们认为这些奖项从未被遗弃过。

我的代码或多或少是

select t1.exhibitions, t2.exhibitions

from (
  select exhibitions.premioc
  from exhibitions
  where EXISTS (select exhibitions.priceC
          from exhibitions
          join presentCo on exhibitions.id_e = presentCo.id_e
          where presentaco.premiada > 0
          group by exhibitions.priceC
          )
  ) as  t1

left outer join (select exhibitions
      from exhibitions
      where EXISTS (select exhibitions.priceF
          from exhibitions
          join presentFo on exhibitions.id_e = presentFo.id_e
          where presentafo.preiceC > 0
          group by exhibitions.priceF
          )

  ) as "t2"

on t1.exhibitions= t2.exhibitions;

我的问题是，我有点不知道SQL中的语法，并且在交付前的最后一刻（学校作业）摸索。我试图搜索并让事情发挥作用，但我不知道我对这部分做错了什么。任何指针都很棒。非常感谢你的任何事情

编辑：当我发布它的时候已经深夜了，我从来没有提到真正的问题，我得到了SQL错误：ORA-00933：SQL命令没有正确结束而且没有真正理解。

Answer 1

有：

所有奖品的总和
分发于展览会，直至2017年8月31日

查询看起来像这样：

select sum(prize_money)
from exhibitions
where exhibition_date < '2017-09-01'

我怀疑答案比你第一次想到的要简单得多

----

我现有的查询有几个问题，我看到了：

select t1.exhibitions  -- this column is not returned by subquery t1
, t2.exhibitions

from (
  select exhibitions.premioc  -- only this column is returned by subquery t1
  from exhibitions
  where EXISTS -- when using EXISTS you need a "correlation" inside the where clause of the subquery
         (select exhibitions.priceC
          from exhibitions
          join presentCo on exhibitions.id_e = presentCo.id_e
          where presentaco.premiada > 0  -- there is NO "correlation" here
          group by exhibitions.priceC
          )
  ) as  t1

left outer join (select exhibitions
      from exhibitions
      where EXISTS ( -- when using EXISTS you need a "correlation" inside the where clause of the subquery
          select exhibitions.priceF
          from exhibitions
          join presentFo on exhibitions.id_e = presentFo.id_e
          where presentafo.preiceC > 0  -- there is NO "correlation" here
          group by exhibitions.priceF
          )

  ) as "t2"

on t1.exhibitions= t2.exhibitions;

----

我建议您需要开始新的，也许以此为起点？

  SELECT
        exhibitions.id_e
      , COALESCE(c.prize_c, 0) prize_c
      , COALESCE(f.prize_f, 0) prize_f
  FROM exhibitions
  LEFT JOIN (
        SELECT
              presentCo.id_e
            , SUM(prize) prize_c
        FROM presentCo
        GROUP BY
              presentCo.id_e
  ) AS c ON exhibitions.id_e = c.id_e
  LEFT JOIN (
        SELECT
              presentFo.id_e
            , SUM(proze) price_f
        FROM presentFo
        GROUP BY
              presentFo.id_e
  ) AS f ON exhibitions.id_e = presentFo.id_e

但我不会尝试进一步的建议，除非我看到＆＃34;样本数据＆＃34; （对于每个表）和＆＃34;预期结果＆＃34;

我如何加入这两个选择，我做错了什么？

1 个答案:

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