MySQL语句在phpmyadmin中工作，但在代码中不起作用

Question

I have the following piece of code. It works when executed in the sql interface of phpmyadmin but when I execute it on the server $stmt = $con->prepare($sql) always returns false and I exit with an error.

Note that $stmt = $con->prepare($sql) does not return an error messages. I'm afraid I might be doing something wrong here too?

I assume I'm missing something important here!

Also the Update statement worked correctly before I modified it to return a comma separated list of updated IDs.

$sql = "SET @uids := null;
                    UPDATE userpicks, brackets
                    SET userpicks.player1 = ?, userpicks.pick = ?
                    WHERE userpicks.id_user = ? AND userpicks.id_tournament = ? AND brackets.stage > ? AND userpicks.player1 = ?
                    AND ( SELECT @uids := CONCAT_WS(',', brackets.id, @uids) );
                    SELECT @uids;";

        if ($stmt = $con->prepare($sql)) {
            $stmt->bind_param('iiiiii', $noPlayerID, $noPlayerID, $_SESSION ["id"], $id_tournament, $bracket_stage, $id_player);
        } else {
            echo mysqli_error($con);
            return getJSONArrayError("Error occurred");
        }

Answer 1

I think you are mixing up Procedural and OOP approach in PHP http://php.net/manual/en/mysqli.quickstart.dual-interface.php Try $stmt=mysqli->prepare($con,$sql) instead of ($stmt = $con->prepare($sql))