If the original query has 8 columns, the page will likely load normally or show an extra row of empty data.
This specific string is designed to be appended to a vulnerable input field (the {KEYWORD} in your example) to probe the database structure: : Closes the original string literal in the SQL query. If the original query has 8 columns, the
The payload you provided, ' UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL-- , is a common pattern used in to determine the number of columns returned by an original database query. What this Payload Does What this Payload Does : Attempts to select
: Attempts to select 8 columns of "null" data. ' UNION ALL SELECT NULL
NULL is used because it is compatible with almost any data type (string, integer, date, etc.), ensuring the query won't fail due to data type mismatches.