Failing to recognize fetch_assoc method - php

Question

I'm trying to upload an excel file to my site and save the data in my database, however i'm failing to do so and getting: Fatal error: Call to undefined method mysqli::fetch_assoc() ... But i'm not sure how to handle it, and i haven't found a question related on SO, any help?
function getSchedule($filepath,$con,$filename){
require_once 'excel/PHPExcel/IOFactory.php';
$objPHPExcel = PHPExcel_IOFactory::load($filepath);
foreach ($objPHPExcel->getWorksheetIterator() as $worksheet) {
$worksheetTitle = $worksheet->getTitle();
$highestRow = $worksheet->getHighestRow(); // e.g. 10
$highestColumn = $worksheet->getHighestColumn(); // e.g 'F'
$highestColumnIndex = PHPExcel_Cell::columnIndexFromString($highestColumn);
list($location, $date) = explode('-', $filename, 2);
$LastChange = date('d/m/Y h:i:s');
$Status='Open';
$servername = "localhost";
$username = "root";
$password = "Js";
$dbname = "jr";
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT * FROM Schedule";
$conn->query($sql);
// output data of each row
while($row = $conn->fetch_assoc()) {
$sql1="DELETE FROM `schedule` WHERE " . $row["Date"]. "='$date'";
$result = mysqli_query($conn,$sql1);
}
$conn->close();
for ($row = 3; $row <= $highestRow; ++ $row) {
$sql="INSERT INTO `schedule` (`Status`,`LastChange`, `Location`,`Date`,`AFNumber`,`Name`,`01-IN`, `01-OUT`, `02-IN`, `02-OUT`, `03-IN`, `03-OUT`, `04-IN`, `04-OUT`, `05-IN`, `05-OUT`, `06-IN`, `06-OUT`, `07-IN`, `07-OUT`, `08-IN`, `08-OUT`, `09-IN`, `09-OUT`, `10-IN`, `10-OUT`, `11-IN`, `11-OUT`, `12-IN`, `12-OUT`, `13-IN`, `13-OUT`, `14-IN`, `14-OUT`, `15-IN`, `15-OUT`, `16-IN`, `16-OUT`, `17-IN`, `17-OUT`, `18-IN`, `18-OUT`, `19-IN`, `19-OUT`, `20-IN`, `20-OUT`, `21-IN`, `21-OUT`, `22-IN`, `22-OUT`, `23-IN`, `23-OUT`, `24-IN`, `24-OUT`, `25-IN`, `25-OUT`, `26-IN`, `26-OUT`, `27-IN`, `27-OUT`, `28-IN`, `28-OUT`, `29-IN`, `29-OUT`, `30-IN`, `30-OUT`, `31-IN`, `31-OUT`) VALUES ('".$Status."', '".$LastChange."','".$location."','".$date."',";
for ($col = 0; $col < ($highestColumnIndex -1); ++ $col) {
$cell = $worksheet->getCellByColumnAndRow($col, $row);
$val = $cell->getValue();
if($col==($highestColumnIndex -2)){
$sql.="'$val'";
}else{
$sql.="'$val', ";}
}
echo "Index:".$highestColumnIndex."<br>";
if($highestColumnIndex < 63){
$temp = 63 - $highestColumnIndex;
for($i = 1;$i <= $temp; $i++){
if($i == $temp){
$sql.=",''";
} else{
$sql.=", '',";
}
}
}
$sql .=")";
if ($con->query($sql) === TRUE) {
} else {
echo "<br><br>Error: " . $sql . "<br>" . $con->error;
}
}//End For Each Row
}//End For Each Worksheet
}//End getHours Function

Answer 1

From php.net:
array mysqli_result::fetch_assoc ( void )
This means that you should provide it with a result of a query, not a connection. Change your code to this and it should work
$results = $conn->query($sql); //assign query to a variable and get mysqli_result in return
while($row = $results->fetch_assoc()) { //use that in the while loop

Answer 2

You are overwriting the connection object $conn.Use
$result = $conn->query($sql);
while($row = $result->fetch_assoc()) {

Answer 3

Try this:
$sql = "SELECT * FROM Schedule";
$result = $conn->query($sql);
// output data of each row
while($row = $result->fetch_assoc()) {