Java 最小化oracle数据库查询

我有一个java应用程序，我在其中执行以下查询以获取数据

SELECT prod.product_id,
       prod.product_name,
       product.stock,
       st.status_code,
       st.status_desc,
       usr1.user_nameas AS soldby,
       usr2.user_nameas soldto
  FROM product prod
  JOIN status ON prod.status_code = st.status_code
  LEFT JOIN user usr1 ON prod.agent_id = usr1.user_id
  LEFT JOIN user usr2 ON prod.buyer_id = usr2.user_id
WHERE condition on dates and PROD.STATUS_CODE IN (<<4 inputs>>)

问题是，如果第一个查询根据日期范围返回太多记录，我需要迭代/循环这些多次2次，以获取最后2个查询的DB记录。是否有人建议/指导我给出一些建议，如何最大限度地减少到DB的往返，以便一次性获取数据

我尝试在产品id上使用和划分稠密等级，但失败了，因为它提供的记录比原始记录多

仅供参考：我正在使用oracle 12C

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任何提示都将不胜感激，提前感谢。

谢谢每一位，我终于得到了答案。 下面是我遵循的过程，很抱歉，我没有访问整个模式的权限。我将在一段时间内发布DDL

以下是我最终编写的查询，以满足我的需求

    WITH 

PROD_RPT AS (
    SELECT prod.product_id as prodId,
       prod.product_name,
       product.stock,
       st.status_code,
       st.status_desc,
       usr1.user_nameas AS soldby,
       usr2.user_nameas soldto,
       itm.status_code as itmStatus,
       itm. returned as returned,
       stk.status_code as stkStatus
  FROM product prod
  JOIN items itm ON prod.product_id = itm.product_id
  LEFT JOIN stk stk ON st.item_id = itm.item_id
  JOIN status ON prod.status_code = st.status_code
  LEFT JOIN user usr1 ON prod.agent_id = usr1.user_id
  LEFT JOIN user usr2 ON prod.buyer_id = usr2.user_id
  WHERE condition on dates and PROD.STATUS_CODE IN (<<4 inputs>>)
),

ITM_RPT AS (
  SELECT * FROM (
    select count(*) Over(partition by rpt.prodId, rpt.itmStatus ORDER BY rpt.prodId, rpt.itmStatus) cnt,
    row_number() Over(partition by rpt.prodId, rpt.itmStatus ORDER BY rpt.prodId, rpt.itmStatus) rn,
    rpt.*
    FROM PROD_RPT rpt WHERE rpt.returned = 1
  ) where rn = 1
),
ITM_STK_RPT AS (
  SELECT * FROM (
    select count(*) Over(partition by rpt.prodId, rpt.stkStatus ORDER BY rpt.prodId, rpt.stkStatus) cnt,
    row_number() Over(partition by rpt.prodId, rpt.stkStatus ORDER BY rpt.prodId, rpt.stkStatus) rn,
    rpt.*
    FROM PROD_RPT rpt
  ) where rn = 1
)

SELECT * FROM ITM_RPT
UNION ALL 
SELECT * FROM ITM_STK_RPT

---

如果有一种功能齐全的数据库编程语言，我们就可以用于这类任务，避免多次往返@WilliamRobertson——我相信这算是好的，更具建设性：您可以通过在PL/SQL过程中编码逻辑来减少往返次数。这可以完成包括获取产品列表在内的全部工作，也可以是为每个产品调用一次以一次性处理两个项目计数任务；DML语句，例如代表您的问题的数据；应如何处理数据的英文非代码说明；以及通过您的流程的样本数据的预期输出。可以通过一次查询或编写PL/SQL过程来执行数据库中的所有步骤，但如果没有更多信息，则很难确定您在做什么。@MT0哪里可以上载我的DDL，是否有网站，请告诉我，以便我可以准备并上载它们。谢谢你的回复。

    WITH 

PROD_RPT AS (
    SELECT prod.product_id as prodId,
       prod.product_name,
       product.stock,
       st.status_code,
       st.status_desc,
       usr1.user_nameas AS soldby,
       usr2.user_nameas soldto,
       itm.status_code as itmStatus,
       itm. returned as returned,
       stk.status_code as stkStatus
  FROM product prod
  JOIN items itm ON prod.product_id = itm.product_id
  LEFT JOIN stk stk ON st.item_id = itm.item_id
  JOIN status ON prod.status_code = st.status_code
  LEFT JOIN user usr1 ON prod.agent_id = usr1.user_id
  LEFT JOIN user usr2 ON prod.buyer_id = usr2.user_id
  WHERE condition on dates and PROD.STATUS_CODE IN (<<4 inputs>>)
),

ITM_RPT AS (
  SELECT * FROM (
    select count(*) Over(partition by rpt.prodId, rpt.itmStatus ORDER BY rpt.prodId, rpt.itmStatus) cnt,
    row_number() Over(partition by rpt.prodId, rpt.itmStatus ORDER BY rpt.prodId, rpt.itmStatus) rn,
    rpt.*
    FROM PROD_RPT rpt WHERE rpt.returned = 1
  ) where rn = 1
),
ITM_STK_RPT AS (
  SELECT * FROM (
    select count(*) Over(partition by rpt.prodId, rpt.stkStatus ORDER BY rpt.prodId, rpt.stkStatus) cnt,
    row_number() Over(partition by rpt.prodId, rpt.stkStatus ORDER BY rpt.prodId, rpt.stkStatus) rn,
    rpt.*
    FROM PROD_RPT rpt
  ) where rn = 1
)

SELECT * FROM ITM_RPT
UNION ALL 
SELECT * FROM ITM_STK_RPT