卡在一个问题陈述中，该陈述包括比较两个表的数据

Question

PFB问题陈述。我尝试使用 dense_rank ，保持功能但不知何故我无法破解它。谁能帮忙。这是用于表示问题的小数据集。原始表有几百万行。

数据集的脚本：

CREATE TABLE TRANSACTION (  
    ITEM VARCHAR2(25 BYTE), 
    LOCATION NUMBER(10,0), 
    TRAN_DATE DATE, 
    POST_DATE DATE 
) 


Insert into TRANSACTION (ITEM,LOCATION,TRAN_DATE,POST_DATE) values ('13252099',473,to_date('09-JUL-18','DD-MON-RR'),to_date('09-JUL-18','DD-MON-RR'));
Insert into TRANSACTION (ITEM,LOCATION,TRAN_DATE,POST_DATE) values ('13252099',473,to_date('25-JUL-18','DD-MON-RR'),to_date('25-JUL-18','DD-MON-RR'));
Insert into TRANSACTION (ITEM,LOCATION,TRAN_DATE,POST_DATE) values ('13252098',470,to_date('09-JUL-18','DD-MON-RR'),to_date('09-JUL-18','DD-MON-RR'));
Insert into TRANSACTION (ITEM,LOCATION,TRAN_DATE,POST_DATE) values ('13252098',470,to_date('28-JUL-18','DD-MON-RR'),to_date('28-JUL-18','DD-MON-RR'));



CREATE TABLE RETAIL_DESC (  
    ITEM VARCHAR2(25 BYTE), 
    LOC NUMBER(10,0), 
    UNIT_RETAIL NUMBER(20,4), 
    ACTION_DATE DATE 
)  


Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252099',473,379.97,to_date('09-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252099',473,299.97,to_date('22-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252099',473,0.01,to_date('19-AUG-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252099',473,379.97,to_date('25-AUG-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252098',470,500.18,to_date('08-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252098',470,299.97,to_date('09-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252098',470,0.01,to_date('19-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252098',470,379.97,to_date('24-JUL-18','DD-MON-RR'));
Insert into RETAIL_DESC (ITEM,LOC,UNIT_RETAIL,ACTION_DATE) values ('13252098',470,300,to_date('24-JUL-18','DD-MON-RR'));

enter image description here

注意：我使用的是 oracle 11g 数据库。 1.Table Retail_desc 包含特定位置的商品的 unit_retail（价格）。 Action_date 是该商品的 unit_retail 更新为该特定位置的新价格的日期。一个 item/location 组合可以有多个 action_date，具体取决于价格更新为新价格的天数。

Table 交易包含日期 (tran_date)，商品从特定位置出售给客户的日期（post_date 与 tran_date 相同 - 可以忽略它).

我想知道在特定位置出售给客户的商品的unit_retail（价格）。

补充意见： 1. 对于每个 item/location 组合，我想获取 item/loc 组合在交易期间的零售单位 (tran_date) 2. action_date为unit_retail for item/location随新零售变化的日期。 3. 如果单位零售价在单个 action_date 上多次变化，则取零售价较低的零售价。

Answer 1

您需要一个带有 join 和 row_number:

的子查询

select item, loc, unit_retail, tran_date
from (
  select
      r.item, r.loc, r.unit_retail, t.tran_date
    , row_number() over (partition by r.item, r.loc, t.tran_date order by r.action_date desc, r.unit_retail) as rn
  from transaction t
  inner join retail_desc r on
    t.item = r.item
    and t.location = r.loc
  where t.tran_date >= r.action_date
) t
where rn = 1
order by item desc, loc desc, tran_date

示例数据的输出：

ITEM        LOC     UNIT_RETAIL  TRAN_DATE
13252099    473     379,97       09.07.2018 00:00:00
13252099    473     299,97       25.07.2018 00:00:00
13252098    470     299,97       09.07.2018 00:00:00
13252098    470     300          28.07.2018 00:00:00

Answer 2

我首先想到的是相关子查询：

select t.*,
       (select min(rd.unit_retail) keep (dense_rank first order by rd.acction_date desc)
        from retail_desc rd
        where rd.loc = t.location and rd.item = t.item and
              rd.action_date <= t.post_date
       ) as unit_retail
from transaction t;

但是，使用 lead() 和 join 可能会更好：

select t.*, rd.unit_retail
from transaction t left join
     (select rd.*,
             lead(rd.action_date) over (partition by item, loc order by action_date) as next_action_date
      from retail_desc rd
     ) rd
     on t.location = rd.loc and t.item = rd.item and
        t.post_date >= rd.action_date and
        (t.post_date < rd.next_action_date or rd.next_action_date is null);

dense_rank() 与这个问题没有明显的联系。

卡在一个问题陈述中，该陈述包括比较两个表的数据

stuck in a problem statement which consist of comparing data for two tables

sql

oracle

dense-rank