Oracle - 多区间按权重取值逻辑 ，分时区-多层级-取配置方案https://blog.csdn.net/shijianduan1/article/details/133386281

某业务配置表，按配置的时间区间及组织层级取方案，形成报表展示出所有部门方案的取值；

例如，总公司配置20230101-20231231为方案3， 分公司配置 20230301-20230731  为方案2，部门配置20230601-20231031 为方案1，配置优先级为 部门> 分公司>总公司 ，即啥都没配则使用总公司默认值；

继上一篇拆分多区间后， 再次进行优化，目前有阶段性成果，先记录一下，等后续再有改进再发。

上一篇中 对日期区间的边界日期做了单独的拆分，没有将边界日期和其临界的 日期合并。

本篇中会对其进行优化，  单目前基础脚本只支持2个优先级，如多个优先级则需要 增加多次查询

数据源 L:优先级，2>3 ,  B1 开始日期, E1 结束日期

注意： 这里默认数据源的 日期区间不会重复

拆分后结果

以下是代码

WITH S AS(SELECT 3 AS L, '20230101' AS B1, '20230821' AS E1FROM DUALUNION ALLSELECT 3 AS L, '20230822' AS B1, '20231231' AS E1FROM DUALUNION ALLSELECT 2 AS L, '20230301' AS B1, '20230731' AS E1FROM DUALUNION ALLSELECT 2 AS L, '20230901' AS B1, '20230931' AS E1FROM DUAL UNION ALLSELECT 2 AS L, '20230401' AS B1, '20230631' AS E1FROM DUAL)  
,A AS(SELECT S.*, ROW_NUMBER() OVER(PARTITION BY L   ORDER BY B1) AS N FROM S)   --对优先级重新排序，确保优先级差1
,A2 AS(SELECT A.*, NVL(PRE.E1, 0) B_PRE, NVL(NEX.B1, 20991231) AS E_NEXFROM ALEFT JOIN A PRE ON A.N = PRE.N + 1 AND PRE.L = A.LLEFT JOIN A NEX ON A.N = NEX.N - 1 AND NEX.L = A.LWHERE A.L = 2 ) ,  --同级别的优先级，也是有边界的
A3 AS(SELECT * FROM A WHERE L = 3)
SELECT A3.L, GREATEST(A3.B1, A2.B_PRE)as B2,   A2.B1 as E2 FROM A2, A3 WHERE A3.B1 < A2.B1  AND A3.E1 > A2.B1
UNION ALL
SELECT A3.L, A2.E1 as B2, LEAST(A3.E1, A2.E_NEX) AS E2 FROM A2, A3 WHERE A3.B1 < A2.E1 AND A3.E1 > A2.E1
UNION ALL  select  L, B1, E1 from A2
order by L, B2;