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.
The primary objective of using this payload is . For a UNION operation to work, the injected query must have the exact same number of columns as the original query. NULL is used because it is compatible with
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. NULL is used because it is compatible with
: This is a SQL comment, which tells the database to ignore the rest of the original, legitimate query that follows. The Goal of the Attack NULL is used because it is compatible with