: This part creates a "fake" row of data. Attackers use this to determine the exact number of columns required for the UNION to work, as both queries must have the same number of columns.
: If the page displays the number "34" several times, it confirms the site is vulnerable to SQL injection. -3216' UNION ALL SELECT 34,34,34,34#
: In MySQL, this symbol marks the rest of the original query as a comment , effectively deleting the remaining code (like WHERE clauses or authentication checks) to bypass security. Purpose of This "Piece" : This part creates a "fake" row of data
: This is an intentional "invalid" input (like a negative ID) designed to break the original SQL query's logic and ensure the database returns no results for the first part of the operation. : In MySQL, this symbol marks the rest
: Determining the column count is the first step toward extracting sensitive data, such as usernames and passwords.
In the context of cybersecurity testing or exploitation, this "piece" of code is typically used to: