Tabular Operators

where operator

Filters out a dataset to a branch of rows that meets a condition when executed.

Syntax

| where condition

Arguments

nametypedescription
ConditionbooleanA bool expression over the fields of the dataset, it is then checked for each row in your dataset

Returns

Rows in dataset for which condition is true.

Examples

['sample-http-logs']
| where method == 'GET' and content_type == 'image/jpeg'

Using * has in APL's where Operator

The * has pattern in APL is a dynamic and powerful tool within the where operator. It offers users the flexibility to search for specific substrings across all fields in a dataset without the need to specify each field name individually. This becomes especially advantageous when dealing with datasets that have numerous or dynamically named fields.

Basic where * has Usage

Find events where any fields contains a specific substring.

['sample-http-logs'] 
| where * has "GET"

Combining Multiple Substrings:

Find events where any field contains one of multiple substrings.

['sample-http-logs'] 
| where * has "GET" or * has "text"

Using * has with other operators

Suppose you want to find events where any field contains a substring, and another specific field equals a certain value.

['sample-http-logs'] 
| where * has "css" and req_duration_ms == 1

Advanced Chaining

Filter data based on several conditions, including fields containing certain substrings, then summarize by another specific criterion.

['sample-http-logs']
| where * has "GET" and * has "css"
| summarize Count=count() by method, content_type, server_datacenter

Using with Aggregates

Find the average of a specific field for events where any field contains a certain substring.

['sample-http-logs']
| where * has "japan"
| summarize avg(req_duration_ms)

String Case Transformation

If you're unsure about the case of the substring in the dataset, convert everything to lowercase for comparison.

['sample-http-logs']
| where * has "japan"
| summarize avg(req_duration_ms)

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