查找 SQL 中連續行之間的年份差異？

Question

我正在嘗試根據indicator_id 計算連續行之間的日期差異，以查找差異不超過3 年的情況。

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

我嘗試了以下查詢，但它只返回相同的行，差異為 0

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

請幫忙

Answer 1

查找差異不超過 3 年的案例。

如果這是您想要的，則使用子查詢來獲取先前的值並在外部查詢中進行過濾：

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';