not getting $stmt->error message

[funbinod]

hello all! greetings!

i'm trying to fetch data from a prepared statement and using some variables to pass the query

        $wh = "class=? AND section=?";
        $param = "'ss', $clas, $sec";
        $stmt = $mysqli->prepare("SELECT CONCAT(fname, ' ', lname) AS name, fullid, roll FROM students WHERE $wh AND ay='$ay' AND cid='$cid'");
	if (!$stmt->bind_param($param)) {
		echo "Bind Error: " . $stmt->error;
	}
	?>

this is showing error but only "Bind Error:" not the "$stmt->error". i tried to echo $wh and $param value also and they give the same value as i intend. why this is happening?

please guide.

thanks in advance.

[Ingolme]

An error only occurs after a statement has been executed.

The error here is not a MySQL error, it's a PHP error. You can't pass one single string as multiple arguments of a function, you have to call it like this:

$stmt->bind_param('ss', $clas, $sec)

 

[funbinod]

@Ingolme thank u for the reply! i appreciate your suggestion. but my requirement is something different. i have multiple cases for passing variables to the prepared statement.

value for $wh and $param differ if the case is different.

like - in the above example the value of $wh and $param are set when $sec has different value. but if $sec is not set differently then $wh and $param will have only one parameter.

	if ($sec == 'ALL') {
		$wh = 'class=?';
		$param = "'s', $clas";
	} else {
		$wh = "class=? AND section=?";
		$param = "'ss', $clas, $sec";
	}

how can i solve this issue then?

Edited December 24, 2017 by funbinod

[funbinod]

ok! i solved this like this

	if ($sec == 'ALL') {
		$stmt = $mysqli->prepare("SELECT CONCAT(fname, ' ', lname) AS name, fullid, roll, section FROM students WHERE class=? AND ay='$ay' AND cid='$cid'");
		$stmt->bind_param('s', $clas);
	} else {
		$stmt = $mysqli->prepare("SELECT CONCAT(fname, ' ', lname) AS name, fullid, roll, section FROM students WHERE class=? AND section=? AND ay='$ay' AND cid='$cid'");
		$stmt->bind_param('ss', $clas, $sec);
	}

thank u for being with me and giving some hint!

is there any other good idea to do this?