如何获取表中下一个和下一个下一个日期的值

Question

我们有一个包含 Effective_Date、CVal、CPrice 列的表

我们如何查询表以在 1 行中从这 2 行返回值：

1. 在某个日期之后的下一个日期为 Effective_Date 的行中的 CVal (NextVal) 和 CPrice (NextPrice) 值

2. 来自 #1 的 Effective_Date 之后的下一个日期的 Effective_Date 行中的 CVal (SecondVal) 和 CPrice (SecondPrice) 值

例如：

Effective_Date  CVal   CPrice
01-JAN-19       1       100
01-JAN-20       2       101
01-JAN-21       3       102
01-JAN-22       4       103

说 somedate = '31-DEC-19'

预期结果

（Effective_Date 列中“31-DEC-19”之后的下一个日期是 01-JAN-20，

之后的下一个日期是 01-JAN-21）：

NextVal NextPrice SecondVal SecondPrice
2       101       3         102

谢谢。

使用来自 zip 的答案进行编辑（将“top”替换为 where rownum = 1，因为 top 在我的 Oracle 上不起作用）：

  select t.* from
 (
  lead(CVal, 1) over(order by Effective_Date) as NextVal 
  ,lead(CPrice, 1) over(order by Effective_Date) as NextPrice  
  ,lead(CVal, 2) over(order by Effective_Date) as SecondVal 
  ,lead(CPrice, 2) over(order by Effective_Date) as SecondPrice
  from tbl where Effective_Date >=  '31-DEC-19'
  order by Effective_Date ) t
  where rownum = 1

Answer 1

你可以使用它的窗口函数

    select  
    lead(CVal, 1) over(order by Effective_Date) as NextVal 
    ,lead(CPrice, 1) over(order by Effective_Date) as NextPrice  
    ,lead(CVal, 2) over(order by Effective_Date) as SecondVal 
    ,lead(CPrice, 2) over(order by Effective_Date) as SecondPrice

    from tbl where Effective_Date >=  '31-DEC-19'
    where rownum = 1
    order by Effective_Date 

输出是

NextVal NextPrice SecondVal SecondPrice
2       101       3         102

Answer 2

如果你只想要一行，你可以过滤和排序表格并限制值：

select t.*
from (select t.*
      from t
      where t.effective_date > date '2019-12-31'
      order by t.effective_date
     ) t
where rownum = 1;

然后您可以添加lead() 以从“下一个”行中拉入额外的列：

select t.*
from (select t.*, lead(cval) over (order by effective_date) as next_cval,
             lead(price) over (order by effective_date) as next_price
      from t
      where t.effective_date > date '2019-12-31'
      order by t.effective_date
     ) t
where rownum = 1;