KQL Series – understanding KQL Queries (Part 1)

In my pervious post I wrote about KQL queries that we will write – we also could use some free some samples that Microsoft put up for us to try things out:


But what is a query? Kudos to Microsoft for putting some great definitions up on their site which I’ve used here.


At times you will see reference to Azure Data Explorer and Azure Monitor.
My first experience with KQL was with Azure Monitor – but I will talk to Azure Data Explorer later in this series. Back to queries…

A Kusto query is a read-only request to process data and return results. The request is stated in plain text, using a data-flow model that is easy to read, author, and automate. Kusto queries are made of one or more query statements.

A query consists of one or more query statements, delimited by a semicolon (;).

At least one of these query statements must be a tabular expression statement. The tabular expression statement generates one or more tabular results. Any two statements must be separated by a semicolon. When the query has more than one tabular expression statement, the query has a batch of tabular expression statements, and the tabular results generated by these statements are all returned by the query.

Two types of query statements:

  • Statements that are primarily used by users (user query statements),
  • Statements that have been designed to support scenarios in which mid-tier applications take user queries and send a modified version of them to Kusto (application query statements).

Some query statements are useful in both scenarios.

here are three kinds of user query statements:

All query statements are separated by a ; (semicolon), and only affect the query at hand.

To be honest most of the time I write tabular expressions – let’s have a closer look at this…


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