mysqli_query不会更新数据库，但不会返回错误

I'm trying to update a database from an excel spreadsheet using phpexcel. Everything seems to run normally but the database remains empty.

Here's my code:

<?php

$con=mysqli_connect("localhost","root","password","PIX");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
echo $con->host_info . "
<br><br";

/** PHPExcel_IOFactory */
require_once dirname(__FILE__) . '/Classes/PHPExcel/IOFactory.php';
$fileName = "Highlights.xls";
$objReader = PHPExcel_IOFactory::createReaderForFile($fileName);
$objReader->setReadDataOnly();
$objPHPExcel = $objReader->load($fileName);

$allDataInSheet = $objPHPExcel->getActiveSheet()->toArray(null,true,true,true);

$arrayCount = count($allDataInSheet); // Total Number of rows in the uploaded EXCEL file
echo $arrayCount."<br>";

for($i=1;$i<=$arrayCount;$i++){
  $string = '"'."INSERT INTO data (`pixName`) VALUES ";
  $pixName= trim($allDataInSheet[$i]["A"]);

  $string .= "('".$pixName."')".'"';
  echo $string."<br>";
  mysqli_query ($con, $string);
}

mysqli_close($con);
?>

Now, I find it weird because I checked the value of $string and it is what it's supposed to be:

"INSERT INTO data (pixName) VALUES ('20091202tbg001')"

I do not have any error message but nothing appears in my database. What am I not seeing here?

Thank you all so much for your time.

Please try the following:

for($i=1;$i<=$arrayCount;$i++){
  $string = "INSERT INTO data (`pixName`) VALUES ";
  $pixName= trim($allDataInSheet[$i]["A"]);

  $string .= "('".$pixName."')";
  echo $string."<br>";
  mysqli_query ($con, $string);
}

Your mistake is adding "(double quotes) in this query

You do not need to add "..." quotes in query. Just remove it and check

for($i=1;$i<=$arrayCount;$i++){
  $string = "INSERT INTO data (`pixName`) VALUES "; // Removed quotes 
  $pixName= trim($allDataInSheet[$i]["A"]);

  $string .= "('".$pixName."')"; // Removed quotes 
  echo $string."<br>";
  mysqli_query ($con, $string);
}