查找 SQL 中连续行之间的年份差异？

Question

我正在尝试根据indicator_id 计算连续行之间的日期差异，以查找差异不超过3 年的情况。

year                             indicator_id
--------------------------      ---------------
January 1, 1999, 12:00 AM             1
January 1, 2000, 12:00 AM             1
January 1, 2001, 12:00 AM             1
January 1, 2006, 12:00 AM             1

我想得到的 output 是

year                             indicator_id           Diff
--------------------------      ---------------        ------
January 1, 1999, 12:00 AM             1                  0
January 1, 2000, 12:00 AM             1                  1
January 1, 2001, 12:00 AM             1                  1
January 1, 2006, 12:00 AM             1                  5

我尝试了以下查询，但它只返回相同的行，差异为 0

SELECT indicator_id, 
       year, 
       year - lag(year) over (order by year) as Diff
FROM education_data

请帮忙

Answer 1

查找差异不超过 3 年的案例。

如果这是您想要的，则使用子查询来获取先前的值并在外部查询中进行过滤：

select ed.*
from (select ed.*, lag(year) over (order by year) as prev_year
      from education_data ed
     ) ed
where prev_year >= year - interval '3 year';