-1" OR 5*5=26 --

It looks like a snippet intended for SQL injection testing. Here’s the gist and why it matters for exams:

• 5*5 = 26 is false (since 25 ≠ 26).
• The part with -1" is typically an attempt to break out of a quoted string in an SQL query (the closing quote) and inject an OR condition.
• The trailing -- marks the rest of the line as a SQL comment, so any follow-up checks are ignored.

In many SQL engines, an expression like -1 is treated as true (nonzero). So combined with OR, the attacker tries to force the WHERE clause to evaluate to true, bypassing authentication or other checks.

Important exam-related takeaways:

• 5*5=26 is false, so the only way for the payload to succeed is if the injected part yields a true condition or the query structure is vulnerable.
• The -- comment is a classic way to ignore the rest of the intended query.
• This demonstrates why parameterized queries (prepared statements) and strong input handling are essential.

Defensive notes (how to study for exams or apply in practice):

• Always use parameterized queries (prepared statements) instead of string concatenation for SQL.
• Validate and whiten input; implement allow-lists for expected formats.
• Disable multiple-statement execution if possible; treat errors safely to avoid leaking details.
• Use least-privilege database accounts and proper error handling.
• If you want, I can give you a quick practice problem: convert a vulnerable string-constructed SQL into a safe parameterized query, or craft a few more injection payloads for study (purely for understanding defense, not to exploit).

Would you like a brief practice exercise or a clearer, step-by-step example of how to defend against this kind of input?