{keyword}' Union All: Select Null,null,null,null,null,null,null,null,null-- Vitq

: Combines the results of the original query with a new, malicious query.

(or sometimes -- ): A comment marker that hides the rest of the original SQL query, preventing syntax errors. : Combines the results of the original query

: A random string identifier often used in automated attacks to verify if the injected query is successfully displayed in the application response. Purpose and Workflow SQL injection UNION attacks | Web Security Academy : Combines the results of the original query

This SQL injection payload ( ' UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL-- vITQ ) is a classic technique used in to determine the exact number of columns returned by a vulnerable web application's original database query. Payload Breakdown ' : Closes the original SQL statement's string parameter. : Combines the results of the original query