假设我们有下表:
代码 | Dt |
---|---|
c1 | 2020-10-01 |
c1 | 2020-10-05 |
c1 | 2020-10-09 |
c1 | 2020-10-10 |
c1 | 2020-10-20 |
c2 | 2020-10-07 |
c2 | 2020-10-09 |
c2 | 2020-10-15 |
c2 | 2020-10-16 |
c2 | 2020-10-20 |
c2 | 2020-10-24 |
Code 和 Dt 的组合是独一无二的。行根据 Code 和 Dt 进行排序。数据库是 Oracle 12。 对于每个代码,我想获取其 Dt 列表,与之前选择的 Dt 相比,每个 Dt 大于 7 天。因此,结果应该是:
代码 | Dt |
---|---|
c1 | 2020-10-01 |
c1 | 2020-10-09 |
c1 | 2020-10-20 |
c2 | 2020-10-07 |
c2 | 2020-10-15 |
c2 | 2020-10-24 |
如果日期差异大于 7,我已经尝试过基于 row_number() 的自连接将每一行与其前一行连接起来。在表中。任何解决方案?谢谢
答案 0 :(得分:5)
您可以使用 match_recognize
相对轻松地解决这个问题with data(code, dt) as (
select 'c1', to_date('2020-10-01', 'YYYY-MM-DD') from dual union all
select 'c1', to_date('2020-10-05', 'YYYY-MM-DD') from dual union all
select 'c1', to_date('2020-10-09', 'YYYY-MM-DD') from dual union all
select 'c1', to_date('2020-10-10', 'YYYY-MM-DD') from dual union all
select 'c1', to_date('2020-10-20', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-07', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-09', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-15', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-16', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-20', 'YYYY-MM-DD') from dual union all
select 'c2', to_date('2020-10-24', 'YYYY-MM-DD') from dual
)
select *
from data match_recognize (
partition by code
order by dt
measures
init.dt dt
one row per match
pattern (init less_than_7_days*)
define
less_than_7_days as less_than_7_days.dt - init.dt < 7
)
您只需按代码分区,按日期排序,然后获取日期差异小于 7(与 init 相比)的任何行 init
和 0-many 以下行 (less_than_7_days*
)。您为整个匹配返回 1 行(初始化 + 后续行),其中包含来自 init
答案 1 :(得分:1)
看起来像一个层次查询的案例。 计算对并遍历链
with pairs(Code, Dt, dtnext) as (
select t1.Code, t1.dt, Min(t2.dt)
from tbl t1
join tbl t2 on t1.code=t2.code and t2.dt >= t1.dt + INTERVAL '7' DAY
group by t1.Code, t1.dt
),
h(Code, Dtn) as (
select Code, Min(dt)
from tbl
group by Code
union all
select h.Code, p.dtnext
from h
join pairs p on p.code=h.code and p.Dt= h.dtn
)
select *
from h
order by code, dtn
退货
CODE DTN
c1 01-OCT-20
c1 09-OCT-20
c1 20-OCT-20
c2 07-OCT-20
c2 15-OCT-20
c2 24-OCT-20