MySQL stored procedure caused `Commands out of sync`

Question

Call procedure works all right in MySQL terminal, but in PHP, caused Commands out of sync; you can\'t run this command nowCommands out of sync; you can\'t run this com

Answer 1

This "bug" was happening to me with extremely simple procedure even inside phpmyadmin. The reason was that I was declaring general variables (without the @ prefix). I changed my variables to user-defined variables prefixed with @ and it was solved.