SQL Server：仅过滤包含特定文本的行之后的行

Question

我有一个包含以下列的表格

application_uuid
changed_at_utc
changed_by 
name

我想按application_uuid 和changed_at_utc 排序。然后，我想只过滤紧跟在application_status 具有文本'Ready for Scoring'的行之后的行

使用 Python 和 Pandas，我会做这样的事情......

application_statuses = application_statuses.sort_values(['application_uuid', 'changed_at_utc'], ascending=[True, True]).reset_index(drop=True)
indexes = application_statuses[application_statuses['application_status']=='Ready for Scoring'].index + 1
next_statuses = application_statuses.ix[indexes]

如何使用 SQL 做同样的事情？

Answer 1

根据您的解释，您可以使用lead 函数来执行此操作。

select next_application_status,application_uuid,changed_at_utc,changed_by
from (select t.*,
      lead(application_status) over(order by application_uuid,changed_at_utc) as next_appliaction_status
      from tablename t
      ) t1
where application_status = 'Ready for Scoring'

如果必须为每个 application_uuid 执行此操作，请在 lead 中包含 partition by，如下所示。

select next_application_status,application_uuid,changed_at_utc,changed_by
from (select t.*,
      lead(application_status) over(partition by application_uuid order by changed_at_utc) as next_appliaction_status
      from tablename t
      ) t1
where application_status = 'Ready for Scoring'

如果您需要 所有 application_status Ready for Scoring 之后的行，请获取该特定行的时间戳并选择所有其他更大的时间戳。这假设 application_uuid 最多有一行 Ready for Scoring 状态。

select application_status,application_uuid,changed_at_utc,changed_by
from (select t.*,
      max(case when application_status='Ready for Scoring' then changed_at_utc end) over(partition by application_uuid) as status_time
      from tablename t
      ) t1
where changed_at_utc > status_time