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

Use "allow-lists" to ensure input matches the expected format (e.g., ensuring a ZIP code is only numbers).

This is the #1 defense. It treats user input as literal data, not executable code. Use "allow-lists" to ensure input matches the expected

: 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. the database usually throws an error.