First not null (nnfirst)
Returns the first non-null value of a specified column for each group.
How does it work in the search window?
After grouping the data, select Aggregation in the search window toolbar, then select the First not null operation. You need to specify one argument:
|First of (mandatory)||Any|
The data type of the aggregated values will be the same as the type of the field added as argument.
demo.ecommerce.data table, we want to get the first non-null IP address value in each 5-minute period. Before aggregating the data, the table must be grouped in 5-minute intervals.
The arguments needed for the aggregation are:
- First of - clientIpAddress column
Click Aggregate function and you will see the following result:
How does it work in LINQ?
Group your data using the following structure:
as... to add the new column that will show the aggregated values. This is the syntax for the First not null operation:
See Build a query using LINQ to learn more about grouping and aggregating your data using the LINQ language.
You can copy the following LINQ syntax and try the above example on the
from demo.ecommerce.data group every 5m every 5m select nnfirst(clientIpAddress) as first_nonnull_IP