Maximum (max)

[ 1 Description ] [ 2 How does it work in the search window? ] [ 3 How does it work in LINQ? ]

Description

This operation returns the highest value found in a data set.

How does it work in the search window?

You can use this operation in two different ways; as an Aggregation or Create field operation:

Aggregation: returns the highest value found in a specified field for each grouping occurrence.
Create field: creates a field that shows the highest of the values found in two or more numeric fields.

Aggregation

Before being able to perform this operation, you have to group your data. Be aware that the fields used as arguments for the grouping operation will not be available to select as arguments for the aggregation operation.

After grouping the data, select Aggregation in the search window toolbar, then select the Maximum operation. You need to specify one argument:

Argument	Data type	Description

Argument

Data type

Description

Max of ^mandatory

Last of (alphabetical ordered) ^mandatory

integer, float

string

When the selected argument is a number, the argument will be automatically transformed into Max of and will retrieve the highest value found in the specified field for each grouping occurrence.

When the selected argument is a string, the argument will be automatically transformed into Last of (alphabetically ordered) and will retrieve the last of the alphabetically ordered values found in the specified field for each grouping occurrence.

Be aware that if a string field used as the argument contains null values, they will be considered when ordering alphabetically. Consequently, if the value retrieved is null, it does not mean the operation has failed, only that it is the last value found when ordering alphabetically.

The data type of the aggregated values is integer, float or string.

Create field

Select Create field in the search window toolbar, then select the Maximum operation. You need to add at least two Any number arguments, but you can add as many as required.

Argument	Data type

Argument	Data type
Any number ^mandatory	integer, float
Any number ^mandatory	integer, float

The data type of the values in the new field is integer or float.

Example

Aggregation

In the siem.logtrust.web.activity table, we want to get the last alphabetical value of the city field in each 5-minute period. Before aggregating the data, the table must be grouped in 5-minute intervals. Then we will perform the aggregation using the Maximum operation.

The arguments needed for the Maximum operation are:

Last of (alphabetically ordered) → city field

Click Aggregate function and you will see the following result:

Create field

In the siem.logtrust.web.activity table, we want to get the highest of values found in the ContentLength and responseTime fields.

The arguments needed for the Maximum operation are:

Any Number - contentLength field
Any Number -responseTime field

Click Create field.

How does it work in LINQ?

Aggregation

Group your data using the following structure:

group every server period by field1, field2...
every client period

Then, use select... as... to add the new field that will show the aggregated values. This is the syntax for the Maximum operation:

max(numeric_field)
max(string_field)

See Build a query using LINQ to learn more about grouping and aggregating your data using the LINQ language.

Create field

Use select... as... to apply the Create field operation. This is the syntax for the Maximum operation:

max(numeric_field1, numeric_field2, numeric_field3...)

Using this operation in Activeboards

Be aware that using the create field version of this operation in Activeboards presents an important limitation: the number of arguments is limited to two.

As a workaround, you can perform subsequent maximum operations until you have obtained the maximum of all the arguments you need. Visit this article for more syntax differences between the Search Window and Activeboards.

Workaround example → select max(number1, number2) as A, max(A, number3) as B, max(B, number4) as C...

Examples

You can copy the following LINQ scripts and try the examples above on the demo.ecommerce.data and siem.logtrust.web.activity tables:

Aggregation

from siem.logtrust.web.activity
  group every 5m
  every 5m
  select max(city) as city_max

Create field

from siem.logtrust.web.activity
  select max(contentLength, responseTime) as maxtimelength