What is used to define a query in a stream processing jobs in Azure Stream Analytics?

Azure Stream Analytics uses a specific query language to define the logic for processing streaming data. This language is a subset of the standard Transact-SQL (T-SQL) language, making it familiar to developers and analysts who have experience with SQL. The query defines how data is read from one or more inputs, transformed, and then written to one or more outputs. This SQL-like syntax is used to express complex temporal logic and aggregations over streams of events.

A. XML: XML is a markup language used for encoding data in a structured format, not for defining real-time data processing logic or queries.
B. KQL: Kusto Query Language (KQL) is used for querying data in Azure Data Explorer, Azure Monitor Logs, and Microsoft Sentinel, not Azure Stream Analytics.
C. YAML: YAML is a data serialization language commonly used for configuration files and data exchange, not for writing data transformation queries.

1. Microsoft Learn, "Stream Analytics Query Language (SAQL) overview": In the introduction, it states, "Azure Stream Analytics offers a SQL query language for performing transformations and computations over streams of events."

2. Microsoft Learn, "DP-900: Explore stream processing with Azure Stream Analytics": Under the "Write queries for Azure Stream Analytics" unit, the first paragraph states, "Azure Stream Analytics jobs are defined with a SQL-like query to transform a stream of data from one or more inputs and write the results to one or more outputs."

3. Microsoft Learn, "Get started with Azure Stream Analytics": In the "Define the transformation query" section of the tutorial, it explicitly states, "The job uses a query language that's a subset of SQL to define the transformation."