问题描述
ID EFF_DT END_DT
FLA1 2018-01-01 00:00:00 2019-12-31 00:00:00
FLA1 2020-01-01 00:00:00 9999-12-31 00:00:00
上述结构需要拆分。并且拆分应该基于日期。
输出中应将其他列作为年份
ID EFF_DT END_DT YEAR
FLA1 2018-01-01 00:00:00 2019-12-31 00:00:00 2019
FLA1 2020-01-01 00:00:00 2020-12-31 00:00:00 2020
FLA1 2021-01-01 00:00:00 9999-12-31 00:00:00 2021
我正在为此目的使用union,它正在生成重复项。任何其他方法/优化解决方案都可以使用。预先感谢。
解决方法
您可以使用递归子查询分解子句:
WITH split ( ID,EFF_DT,END_DT,MAX_DT ) AS (
SELECT id,eff_dt,LEAST(
ADD_MONTHS( TRUNC( SYSDATE,'YY' ),12 ) - INTERVAL '1' DAY,end_dt
),end_dt
FROM table_name
UNION ALL
SELECT id,end_dt + INTERVAL '1' DAY,max_dt,max_dt
FROM split
WHERE end_dt < max_dt
)
SELECT id,end_dt
FROM split;
其中,为您的示例数据:
CREATE TABLE table_name ( ID,END_DT ) AS
SELECT 'FLA1',DATE '2018-01-01',DATE '2019-12-31' FROM DUAL UNION ALL
SELECT 'FLA1',DATE '2020-01-01',DATE '9999-12-31' FROM DUAL;
输出:
ID | EFF_DT | END_DT :--- | :------------------ | :------------------ FLA1 | 2018-01-01 00:00:00 | 2019-12-31 00:00:00 FLA1 | 2020-01-01 00:00:00 | 2020-12-31 00:00:00 FLA1 | 2021-01-01 00:00:00 | 9999-12-31 00:00:00
db 提琴here
,如果要生成所有年的数据,则:
with cte (id,end_dt,orig_end_dt)
select id,end_dt
from t
union all
select cte.id,end_dt + interval '1' day,least(orig_end_dte,trunc(end_dt,'YYYY') + interval '1' year
from cte
where trunc(eff_dt,'YYYY') < trunc(end_dt,'YYYY')
)
select id,to_char(end_dt,'YYYY') as year
from cte;
注意:此期间内,每年每年都会单独产生一行。
如果您希望限制年份,则可能是这样:
with cte (id,'YYYY') < least(trunc(end_dt,'YYYY'),date '2021-01-01')
)
select id,(case when end_dt = date '2021-12-31' then orig_end_dt else end_dt end),'YYYY') as year
from cte;