Union All Select Null,'qbqvq'||'zztyernefl'||'qqbqq',null,null,null,null,null,null,null-- Ijiy: {keyword}

: This is a comment marker in SQL. It tells the database to ignore everything that comes after it, effectively "breaking" the rest of the original, legitimate code so it doesn't cause an error. A Helpful Story: The Librarian and the Hidden Note

The string you provided is a classic example of a used for a "UNION-based" attack. The "Anatomy" of the Payload : This is a comment marker in SQL

You go to the librarian (the website) and ask, "Show me all books about Gardening " (the KEYWORD ). finds the gardening books

The librarian goes to the back (the database), finds the gardening books, and brings them to you. and brings them to you.