SQL Lag or Lead - 如何根据日期/时间字段不同的行选择记录

Question

我有一个包含数百万条记录的表，其中包含日期/时间戳 - 我正在尝试返回存在差异 > 给定秒数的记录。

该表包含日期/时间戳，但我无法使用位置和计算出的差异。 （createddate 是日期字段，updatedon 是日期/时间）

SELECT createddate,
       LEAD(createddate, 1) OVER (ORDER BY createddate) AS created_next,
       LEAD(createddate, 1) OVER (ORDER BY createddate) - createddate AS created_diff, 
       LEAD(updatedon, 1) OVER (ORDER BY updatedon) AS created_next,
       LEAD(createddate, 1) OVER (ORDER BY updatedon) - updatedon AS Updatedon_diff
FROM   gsdaudit
--WHERE created_diff >  1000
ORDER BY updatedon_diff

Answer 1

最简单的方法（假设是 SQL 服务器）可能是使用DATEDIFF 来获取以秒为单位的差异，并将计算放在一个公用表表达式中；

WITH cte AS (
  SELECT 
    createddate,
    DATEDIFF(second, createddate, 
             LEAD(createddate, 1) OVER (ORDER BY createddate)) created_diff,
    updatedon,
    DATEDIFF(second, createddate, 
             LEAD(updatedon,   1) OVER (ORDER BY updatedon  )) updatedon_diff
  FROM   gsdaudit
)
SELECT * FROM cte 
WHERE created_diff >  10 OR updatedon_diff > 10

An SQLfiddle to test with.

编辑：Oracle 的相同查询；

WITH cte AS (
  SELECT 
    createddate,
    (LEAD(createddate, 1) OVER (ORDER BY createddate)-createddate)*24*60*60 created_diff,
    updatedon,
    (LEAD(updatedon, 1) OVER (ORDER BY updatedon)-updatedon)*24*60*60 updatedon_diff
  FROM   gsdaudit
)
SELECT * FROM cte 
WHERE created_diff >  10 OR updatedon_diff > 10

Another SQLfiddle.