Execute more queries "PHP"

Short version: the approach in the original post runs into two separate problems — the older mysql API and unsafe testing practices. As @somedude3488 hinted, that API is not suited for sending arbitrary semicolon-separated statements in one shot; also the old ext/mysql is removed in modern PHP, so new code should use PDO or MySQLi instead (PHP migration notes). If you truly need to run multiple statements in one call, MySQLi exposes mysqli::multi_query, but it requires careful result-set handling and is generally unnecessary for normal workflows (mysqli::multi_query).

Practical, safer steps to apply right now: 1) Move to parameterized queries (PDO or MySQLi prepared statements) so user input cannot corrupt SQL; follow the OWASP prevention guidance for SQL injection. 2) Run each logical SQL operation in its own API call or use transactions to keep multi-step changes atomic. 3) Test only on isolated, backed-up development copies (local VM or disposable container) and avoid experimenting on production data. 4) Use clear error checking and logging so you can see why a statement failed instead of sending many statements at once.

For a next action: refactor the example to use prepared statements and execute two separate statements (or a transaction) rather than concatenating semicolons. See the PDO and MySQLi docs for patterns and the OWASP cheat sheet for prevention techniques (SQL Injection Prevention Cheat Sheet).