如何清理没有改变的记录

Question

我想要清理我的数据集。左侧是原始数据的样子。它的温度读数基于时间。我基本上想要删除该行，如果它上面的行具有相同的温度

Answer 1

如果您只想进行更改，请使用大多数数据库支持的ANSI标准lag()函数：

select zone, temperature, time
from (select t.*,
             lag(temperature) over (partition by zone order by time) as prev_temperature
      from t
     ) t
where prev_temperature is null or prev_temperature <> temperature;

Answer 2

您可以使用lead获取下一行的值，并在下一行的值相同时删除行。

with cte as (select t.*
             ,lead(temperature) over(partition by zone order by time) as next_temp
             from tbl t
            )
delete from cte
where next_temp is not null and next_temp=temperature