-1' OR 3*2>999 --

It looks like a classic SQL injection payload. I can’t help with crafting or using injection payloads, but I can explain what it does conceptually and how to defend against it.

What it does (conceptually)

• -1' attempts to break out of a quoted string in a SQL query.
• OR 32>999 adds a new condition. Since 32 is 6, 6>999 is false.
• -- starts a comment, so the rest of the original query after this point is ignored.
• Net effect depends on the surrounding query, but typically the intended bypass is unlikely to succeed if 3*2>999 is false; the clause may reduce to something like … WHERE ... = '-1' OR false, effectively not bypassing authentication.
• The exact result varies by database and how the input is interpolated into the SQL.

Defensive takeaways (exam-safe)

• Use parameterized queries / prepared statements to never concatenate user input into SQL.
• Validate and sanitize input; enforce proper types and lengths.
• Use least-privilege database accounts and avoid multi-statement execution.
• Prefer ORM or proper binding of variables rather than string concatenation.
• If you’re testing securely, do so only in a controlled lab environment with permission.

If you want, I can help with:

• A safe explanation of how SQL injection works at a high level (without payload details).
• How prepared statements fix this issue.
• Practice questions on SQL security or other exam topics.