どのように永遠のループなしで各期間の再帰を行うには？

Question

各plan_periodごとに期間を再帰的に計算しようとすると、永遠のループでクエリが停止しました。以下は、私がしようとしているされているもの：

WITH p (period_id, start_period, end_period ) 
     AS (SELECT 
        PERIOD_VERSIO, 
        To_date(FROM_PERIOD, 'YYYYMM'), 
        To_date(TO_PERIOD, 'YYYYMM') 
      FROM SOR_MAP_PLAN_PERIOD), 
     date_ranges 
     AS (SELECT 
        distinct 
        period_id, 
        To_char(start_period, 'YYYYMM') as START_PERIOD, 
        To_char(Add_months (start_period, LEVEL - 1), 'YYYYMM') as END_PERIOD 
      FROM p 
      CONNECT BY LEVEL <= Months_between(end_period, start_period) + 1) 


    SELECT d.period_id as "KEY", 
     -- d.start_period, 
      d.end_period as PERIOD, 
     e.end_period as PLAN_PERIOD 
    FROM date_ranges d 
    --order by 3,2 

      full outer join (SELECT period_id,end_period 
         FROM date_ranges 
         ) e on e.period_id=d.period_id 
    ORDER BY 3, 2, 1 

    ; 
Parameter table: 

    PERIOD_VERSIO FROM_PERIOD TO_PERIOD 
    201612_BU  201701  201712 
    201705_STR  201801  202012 
    201706_SRT1  201801  202012 
    201709_LE  201710  201809 

募集結果：

PERIOD_VERSIO PERIOD PLAN_PERIOD 
201612_BU  201701 201701 
201612_BU  201702 201701 
201612_BU  201703 201701 
201612_BU  201704 201701 
201612_BU  201705 201701 
201612_BU  201706 201701 
201612_BU  201707 201701 
201612_BU  201708 201701 
201612_BU  201709 201701 
201612_BU  201710 201701 
201612_BU  201711 201701 
201612_BU  201712 201701 
201612_BU  201701 201702 
201612_BU  201702 201702 
201612_BU  201703 201702 
201612_BU  201704 201702 
…..  
…..  
201706_SRT1  201801 201801 
201706_SRT1  201802 201801 
201706_SRT1  201803 201801 
201706_SRT1  201804 201801 
201706_SRT1  201805 201801 
201706_SRT1  201806 201801 
201706_SRT1  201808 201801 
201706_SRT1  201808 201801 
201706_SRT1  201809 201801 
201706_SRT1  201810 201801 
201706_SRT1  201811 201801 
201706_SRT1  201812 201801 
……  
201706_SRT1  201801 202012 
201706_SRT1  201802 202012 
201706_SRT1  201803 202012 
201706_SRT1  201804 202012 
201706_SRT1  201805 202012 
201706_SRT1  201806 202012 
201706_SRT1  201808 202012 
201706_SRT1  201808 202012 
201706_SRT1  201809 202012 
201706_SRT1  201810 202012 
201706_SRT1  201811 202012 
201706_SRT1  201812 202012 

Answer 1

あなたのクエリはこのように簡単かもしれない：

select period_versio 
     ,ym as period 
     ,from_period plan_period 
    from parameter_t a 
    join periods_t b on(
     b.ym >= a.from_period 
    and b.ym <= a.to_period 
); 

...あなたは彼らと多くの作業する場合、あなたはおそらく持つべき期間...のテーブルを持っていた場合。 2000年から2030年の期間の表を作成する方法は次のとおりです。私は例から、次のテーブル構造を想定している

create table periods_t(
    ym number not null 
    ,year number not null 
    ,month number not null 
    ,primary key(ym) 
); 

insert 
    into periods_t(ym, year, month) 
select year || lpad(month, 2, '0') as ym 
     ,year 
     ,month 
    from (select 1999 + level as year from dual connect by level <= 30) y 
     ,(select level as month  from dual connect by level <= 12) m; 

は

create table parameter_t(
    period_versio varchar2(20) not null 
    ,from_period number(6) not null 
    ,to_period  number(6) not null 
); 

insert into parameter_t values('201612_BU',  201701, 201712); 
insert into parameter_t values('201705_STR', 201801, 202012); 
insert into parameter_t values('201706_SRT1', 201801, 202012); 
insert into parameter_t values('201709_LE',  201710, 201809); 

Answer 2

これは純粋なSQLで行うことができます。

最初に、各period_versio'. Then there's join two instances of that subquery which produces all the permutations of generated months for the period_versio 'の開始期間と終了期間にまたがるすべての月を生成する再帰WITH節があります。

with mths (period_id, period_st, period_end, lvl) as (
    select period_versio, 
      cast(to_date(from_period, 'yyyymm') as date), 
      cast(to_date(to_period, 'yyyymm') as date), 
      1 
    from sor_map_plan_period 
    union all 
    select period_id, 
      cast(add_months(period_st, 1) as date), 
      cast(period_end as date), 
      lvl+1 
    from mths 
    where lvl < months_between(period_end, period_st) 
) 
select t1.period_id as period_versio 
     ,to_char(t1.period_st, 'yyyymm') as period 
     ,to_char(t2.period_end, 'yyyymm') as plan_period 
from  
(select period_id, 
     period_st 
    from mths) t1 
join 
(select period_id, 
      period_end 
from mths) t2 
on t1.period_id = t2.period_id 
order by 1, 2, 3 
/

---

WITH句の再帰は、Oracle 11gR2の中で紹介されました。 ORA-01790を出して、日付を渡すと厄介なバグがあります。したがって、明らかに既に日付のものを奇妙に見えるCAST式の必要性が必要です。あなたが12cで作業している場合は、それらを必要としないかもしれません。