有一个表ticket
包含如下所示的数据:
Id Impact group create_date
------------------------------------------
1 3 ABC 2020-07-28 00:42:00.0
1 2 ABC 2020-07-28 00:45:00.0
1 3 ABC 2020-07-28 00:48:00.0
1 3 ABC 2020-07-28 00:52:00.0
1 3 XYZ 2020-07-28 00:55:00.0
1 3 XYZ 2020-07-28 00:59:00.0
预期成果:
Id Impact group create_date
------------------------------------------
1 3 ABC 2020-07-28 00:42:00.0
1 2 ABC 2020-07-28 00:45:00.0
1 3 ABC 2020-07-28 00:52:00.0
1 3 XYZ 2020-07-28 00:59:00.0
目前,这是我使用的查询:
WITH final AS (
SELECT p.*,
ROW_NUMBER() OVER(PARTITION BY p.id,p.group,p.impact
ORDER BY p.create_date desc, p.impact) AS rk
FROM ticket p
)
SELECT f.*
FROM final f
WHERE f.rk = 1
结果,我得到的是:
Id Impact group create_date
-----------------------------------------
1 2 ABC 2020-07-28 00:45:00.0
1 3 ABC 2020-07-28 00:52:00.0
1 3 XYZ 2020-07-28 00:59:00.0
似乎分区依据优先于按值排序。 有没有其他方法可以实现预期的结果。我正在亚马逊Redshift上运行这些查询。
您可以使用LEAD()
来检查行之间的Impact
是否更改,仅获取值将更改的行。
WITH
look_forward AS
(
SELECT
*,
LEAD(impact) OVER (PARTITION BY id, group ORDER BY create_date) AS lead_impact
FROM
ticket
)
SELECT
*
FROM
look_forward
WHERE
lead_impact IS NULL
OR lead_impact <> impact
您似乎想要id
/impact
/group
相对于下一行发生变化的行。 一个简单的方法是查看下一个create_date
整体和小组的下一个create_date
。 如果它们相同,则过滤:
select t.*
from (select t.*,
lead(create_date) over (order by create_date) as next_create_date,
lead(create_date) over (partition by id, impact, group order by create_date) as next_create_date_img
from ticket t
) t
where next_create_date_img is null or next_create_date_img <> next_create_date;