Compare data between current value and previous value - Kusto

Question

I want to find the id value of rows whose humidity

is greater than the previous day humidity.

datatable(id:int, recorddate:datetime, humidity:real)

[

    1, datetime(2022-11-01), 10.0,

    2, datetime(2022-11-02), 12.0,

    3, datetime(2022-11-03), 15.0,

    4, datetime(2022-11-04), 18.0,

    5, datetime(2022-11-05), 20.0,

    6, datetime(2022-11-06), 22.0,

    7, datetime(2022-11-07), 19.0,

    8, datetime(2022-11-08), 16.0,

    9, datetime(2022-11-09), 14.0,

    10, datetime(2022-11-10), 11.0,

];

desired response:

id

2

3

4

5

6

Above ids have values greater than their previous row value.

Answer 1

You could use the prev() function.

For example:

T
| order by record_date asc
| where prev(humidity) < humidity
| project id