Fatal error: uncaught mysqli_SQL_exception: you have an error in your SQL syntax; check the manual that corresponds to your mariadb server version for the right syntax to use

See more:

PHP

MySQL

My error when I try to change the name:
Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'WHERE userId = 2' at line 1 in C:\xampp\htdocs\login2\includes\functions.inc.php:148 Stack trace: #0 C:\xampp\htdocs\login2\includes\functions.inc.php(148): mysqli->query('UPDATE users2 S...') #1 C:\xampp\htdocs\login2\includes\editfac.inc.php(23): updateFacName(Object(mysqli), '2', 'Min, Shan') #2 {main} thrown in C:\xampp\htdocs\login2\includes\functions.inc.php on line 148

My error when I try to change the username:
Fatal error: Uncaught mysqli_sql_exception: Unknown column 'shan' in 'field list' in C:\xampp\htdocs\login2\includes\functions.inc.php:167 Stack trace: #0 C:\xampp\htdocs\login2\includes\functions.inc.php(167): mysqli->query('UPDATE users2 S...') #1 C:\xampp\htdocs\login2\includes\editfac.inc.php(26): updateUsername(Object(mysqli), '1', 'shan') #2 {main} thrown in C:\xampp\htdocs\login2\includes\functions.inc.php on line 167


My Code in includes/function.inc.php:

<?php
function emptyInputEditFac($facid, $name, $username) {
	$result;

	if (empty($facid) && empty($name) && empty($username)) {
		$result = true;
	}
	else {
		$result = false;
	}
	return $result;
}

function updateFacId($conn, $userid, $facid) {
	$sql = "UPDATE users2 SET facId = $facid WHERE userId = $userid;";
	
	if ($conn -> query($sql) === TRUE) {
		echo "Record updated successfully";
		
		header("location: ../faculty.php");
		exit();
	}

	else {
		phpalert("Error updating record: " . $conn->error);

		header("location: ../faculty.php");
		exit();
	}

}

function updateFacName($conn, $userid, $name) {
	$sql = "UPDATE users2 SET name = $name WHERE userId = $userid;";
	
	if ($conn -> query($sql) === TRUE) {
		echo "Record updated successfully";
		
		header("location: ../faculty.php");
		exit();
	}

	else {
		echo("Error updating record: " . $conn->error);

		header("location: ../faculty.php");
		exit();
	}

}

function updateUsername($conn, $userid, $username) {
	$sql = "UPDATE users2 SET username = $username WHERE userId = $userid;";
	
	if ($conn -> query($sql) === TRUE) {
		echo "Record updated successfully";
		
		header("location: ../faculty.php");
		exit();
	}

	else {
		phpalert("Error updating record: " . $conn->error);

		header("location: ../faculty.php");
		exit();
	}

}

My Code in includes/editfac.inc.php:

<?php

if (isset($_POST['submit'])) {
	
	$userid = $_POST["userid"];
	$facid = $_POST["facid"];
	$name = $_POST["name"];
	$username = $_POST["username"];

	require_once 'dbh.inc.php';
	require_once 'functions.inc.php';

	if (emptyInputEditFac($facid, $name, $username) !== false) {
		header("location: ../faculty.php?change=nochange");
		exit();
	}

	else {
		if (!empty($facid)) {
			updateFacId($conn, $userid, $facid);
		}
		if (!empty($name)) {
			updateFacName($conn, $userid, $name);
		}
		if (!empty($username)) {
			updateUsername($conn, $userid, $username);
		}
		exit();
	}

}
else {
	header("location: ../faculty.php");
	exit();
}

My Code in editfac.php:

<section class = "form-sec">
	<div class = "form-div">
		<form id="editfac-form" action="includes/editfac.inc.php" method="post">
			<?php
				if (isset($_POST['user-id'])) {
					$userId = $_POST['user-id'];
					echo "<input type='hidden' name='userid' value='".$userId."'/>";
				}
			?>
			<input type="number" name="facid" placeholder="Faculty ID Number">
			<input type="text" name="name" placeholder="Lastname, Firstname MI.">
			<input type="text" name="username" placeholder="Username">

			<button type="submit" name="submit">Update</button>
		</form>

	</div>
</section>

The updateFacId() function works fine for some reason.

What I have tried:

Searched about the error in Google but I couldn't understand much.