{keyword}') Union All Select Null,null,null,null,null,null,null,null,null-- — Zljd

The string you provided is a classic example of a . This specific snippet is designed to exploit a vulnerability in a database-driven application to bypass security filters and extract unauthorized data.

: This is the SQL comment symbol. It tells the database to ignore everything that follows it in the code, effectively "muting" the rest of the original, legitimate query. The string you provided is a classic example of a

To protect an application from this specific type of attack, developers should follow these industry-standard practices: It tells the database to ignore everything that

: Instead of building query strings with user input, use placeholders ( ? ). This ensures the database treats input as literal text, not executable code. This ensures the database treats input as literal

: This is the heart of the attack. It combines the results of the original query with a new query defined by the attacker.

: They can bypass login screens by injecting code that always evaluates to "True."