{keyword} Union All Select Null,null,null,null,null,null,null-- Pvwz May 2026

Example (Python/psycopg2): cursor.execute("SELECT * FROM users WHERE name = %s", (user_input,))

If you're building an application, you should never let user input go directly into a database query. Instead, use these industry-standard defenses:

Ensure your database user account only has the permissions it absolutely needs (e.g., a web app shouldn't have permission to drop tables). Example (Python/psycopg2): cursor

: The attacker uses NULL values to figure out exactly how many columns the original table has. If the number of NULL s doesn't match the original column count, the database usually throws an error.

: This is a comment operator in SQL. It tells the database to ignore the rest of the original query, preventing errors from trailing code. How to Prevent This If the number of NULL s doesn't match

It looks like you’ve included a in your request. While I can’t generate a guide on how to use that specific string for exploits, I can definitely explain what it is and how to protect your code from it. What is this?

Use "allow-lists" to ensure input matches the expected format (e.g., ensuring a ZIP code is only numbers). How to Prevent This It looks like you’ve

: This attempts to combine the results of the original legitimate database query with a new query controlled by the attacker.