Select 只有一行，按值字段，排序

Question

这个问题从延伸而来，但更笼统（没有产品限制，但按产品价值给出一个）。

我有一个table

DROP TABLE mytable;
CREATE TABLE mytable 
(
    product_code VARCHAR2(20 BYTE) NOT NULL ENABLE, 
    priority NUMBER NOT NULL ENABLE, 
    date_act DATE, 
    date_dis DATE
);

填充 table

INSERT INTO mytable (product_code, priority, date_act, date_dis) VALUES ('bla', '0', TO_DATE('2019-01-01', 'YYYY-MM-DD'), TO_DATE('2019-01-31', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_act, date_dis) VALUES ('bla', '1', TO_DATE('2019-02-01', 'YYYY-MM-DD'), TO_DATE('2019-02-28', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_act) VALUES ('bla', '2', TO_DATE('2019-01-01', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_act) VALUES ('bla', '3', TO_DATE('2019-02-01', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_dis) VALUES ('bla', '4', TO_DATE('2019-01-31', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_dis) VALUES ('bla', '5', TO_DATE('2019-02-28', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority) VALUES ('bla', '6');
INSERT INTO mytable (product_code, priority) VALUES ('bla', '7');

INSERT INTO mytable (product_code, priority, date_act, date_dis) VALUES ('foo', '0', TO_DATE('2019-01-01', 'YYYY-MM-DD'), TO_DATE('2019-01-31', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_act) VALUES ('foo', '1', TO_DATE('2019-02-01', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_dis) VALUES ('foo', '2', TO_DATE('2019-01-31', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority) VALUES ('foo', '3');


INSERT INTO mytable (product_code, priority, date_act, date_dis) VALUES ('tmp', '0', TO_DATE('2019-01-01', 'YYYY-MM-DD'), TO_DATE('2019-01-31', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_act) VALUES ('tmp', '1', TO_DATE('2019-01-01', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority, date_dis) VALUES ('tmp', '2', TO_DATE('2019-02-28', 'YYYY-MM-DD'));
INSERT INTO mytable (product_code, priority) VALUES ('tmp', '3');

内容

SELECT * FROM mytable;

和输出

PRODUCT_CODE           PRIORITY DATE_ACT  DATE_DIS 
-------------------- ---------- --------- ---------
bla                           0 01-JAN-19 31-JAN-19
bla                           1 01-FEB-19 28-FEB-19
bla                           2 01-JAN-19          
bla                           3 01-FEB-19          
bla                           4           31-JAN-19
bla                           5           28-FEB-19
bla                           6                    
bla                           7                    
foo                           0 01-JAN-19 31-JAN-19
foo                           1 01-FEB-19          
foo                           2           31-JAN-19
foo                           3                    
tmp                           0 01-JAN-19 31-JAN-19
tmp                           1 01-JAN-19          
tmp                           2           28-FEB-19
tmp                           3

条件定义

condition_weight 4：当行定义了date_act和date_dis时。
condition_weight 3：当行有 date_dis 定义但 date_act 没有。
condition_weight 2：当行有 date_act 定义但 date_dis 没有。
condition_weight 1：当行有date_act和date_dis未定义时。

如果 condition_weight 4 为真，则左侧（3、2 和 1）将被忽略。

如果 condition_weight 4 为假且 condition_weight 3 为真，则 condition_weight 2 和 condition_weight 1 将被忽略。

如果condition_weight4和3为假而condition_weight2为真condition_weight1将被忽略。

如果 condition_weight 4, 3 和 2 只为假 condition_weight 1 将被评估。

问题：每个product_code如何只获得一行，其优先级最高，输入参数 date_submit with condition weight definitions?

EXAMPLE of OUTPUT Required 注意：以下table结果是手动创建的（我需要类似的结果，但我没有查询）。

DATE_SUBMIT :='2019/01/15'

CONDITION_WEIGHT       PRIO PRODUCT_CODE           PRIORITY DATE_ACT  DATE_DIS  :DATE_SUBMIT                                                                                                                    
---------------- ---------- -------------------- ---------- --------- --------- --------------------------------------------------------------------------------------------------------------------------------
               4          0 bla                           0 01-JAN-19 31-JAN-19 2019/01/15                                                                                                                      
               4          0 foo                           0 01-JAN-19 31-JAN-19 2019/01/15                                                                                                                      
               4          0 tmp                           0 01-JAN-19 31-JAN-19 2019/01/15

DATE_SUBMIT :='2019/02/15'

CONDITION_WEIGHT       PRIO PRODUCT_CODE           PRIORITY DATE_ACT  DATE_DIS  :DATE_SUBMIT                                                                                                                    
---------------- ---------- -------------------- ---------- --------- --------- --------------------------------------------------------------------------------------------------------------------------------
               4          1 bla                           1 01-FEB-19 28-FEB-19 2019/02/15                                                                                                                      
               2          1 foo                           1 01-FEB-19           2019/02/15                                                                                                                      
               3          2 tmp                           2           28-FEB-19 2019/02/15

DATE_SUBMIT :='2018/12/31'

CONDITION_WEIGHT       PRIO PRODUCT_CODE           PRIORITY DATE_ACT  DATE_DIS  :DATE_SUBMIT                                                                                                                    
---------------- ---------- -------------------- ---------- --------- --------- --------------------------------------------------------------------------------------------------------------------------------
               3          5 bla                           5           28-FEB-19 2018/12/31                                                                                                                      
               3          2 foo                           2           31-JAN-19 2018/12/31                                                                                                                      
               3          2 tmp                           2           28-FEB-19 2018/12/31

DATE_SUBMIT :='2019/12/31'

CONDITION_WEIGHT       PRIO PRODUCT_CODE           PRIORITY DATE_ACT  DATE_DIS  :DATE_SUBMIT                                                                                                                    
---------------- ---------- -------------------- ---------- --------- --------- --------------------------------------------------------------------------------------------------------------------------------
               2          3 bla                           3 01-FEB-19           2019/12/31                                                                                                                      
               2          1 foo                           1 01-FEB-19           2019/12/31                                                                                                                      
               2          1 tmp                           1 01-JAN-19           2019/12/31

检查答案结果，但如果有可能更简单的查询。

编辑只有 priority 最高 priority 必须是 .

Answer 1

我认为这应该可以满足您的要求。

select *
from (
    SELECT mytable.*,
        case when date_act is not null and date_dis is not null then 4
                 when date_dis is not null then 3
                 when date_act is not null then 2
                 else 1 end as weight,
        max(case when date_act is not null and date_dis is not null then 4
                 when date_dis is not null then 3
                 when date_act is not null then 2
                 else 1 end) over (partition by product_code) as max_weight
    FROM mytable
    where TO_DATE(:date_submit, 'yyyy/mm/dd') between coalesce(date_act, TO_DATE(:date_submit, 'yyyy/mm/dd'))
                        and coalesce(date_dis, TO_DATE(:date_submit, 'yyyy/mm/dd'))
    ) iv
where weight = max_weight
;

如果您还想按 :product_code 参数进行过滤，就像在您的其他问题中那样，会简单一些。

Answer 2

使用 case when 分配条件权重。然后为每个产品取最佳行，使用 rank():

with 
  d as (select date '2019-02-15' date_submit from dual),
  t as (
    select m.*, case 
                when date_act is not null and date_dis is not null then 4 
                when date_act is null and date_dis is not null then 3
                when date_act is not null and date_dis is null then 2
                else 1 end condition
      from mytable m)
select product_code, priority, date_act, date_dis, condition, date_submit 
  from (
    select t.*, d.*, 
           rank() over ( partition by product_code order by condition desc ) rnk
      from t join d 
        on date_submit between nvl(date_act, date_submit) and nvl(date_dis, date_submit))
  where rnk = 1

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