Data is not inserted into database

Databases
1

Hello,

below is my code. i am trying to insert the data into database but not getting suceeded. In my query there, if i remove the condition WHERE username=‘$u’ it works fine but with it,it responds only in failure.

<?php
$sql = "SELECT * FROM mymake LIMIT 1";
$query = mysqli_query($db_conx,$sql);
$numrows = mysqli_num_rows($query);
?>
<?php
if(isset($_POST["submit"]))
{
	 $ques=preg_replace('#[^a-z0-9]#i', '', $_POST['q']);
	 $ans=preg_replace('#[^a-z0-9]#i', '', $_POST['response']);
	 $sql="INSERT INTO mymakeuser (question1,answer1) VALUES('$ques','$ans') WHERE username='$u' ";
      $user_query = mysqli_query($db_conx, $sql);
	if($user_query===TRUE)
	{echo "success";}
	else echo "failed";
	}

?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style>
form > select { width:280px;}
</style>
</head>
<body>
<form method="post" action="hello.php?u=<?php echo $u; ?>">
<?php
if ($numrows > 0){
  while ($row = mysqli_fetch_array($query, MYSQLI_ASSOC)) {
?>

    <input type="text" name="q" placeholder="<?php echo $row["question"];?>"  size="82"  >
    <select name="response" required="required">
      <option value=""></option>
      <option value="<?php echo $row["option1"]; ?>"><?php echo $row["option1"]; ?></option>
      <option value="<?php echo $row["option2"]; ?>"><?php echo $row["option2"]; ?></option>
      <option value="<?php echo $row["option3"]; ?>"><?php echo $row["option3"]; ?></option>
    </select>
    <br>
<?php
  }
}
?>
<br /><input type="submit" value="Ready to Go" name="submit" />
<input type="reset" value="Reset" name="reset" />
</form>

</body>
</html>
2

that’s because the INSERT VALUES statement doesn’t allow a WHERE clause

3

Then what shall i do. At the time of sign up, i made the entry for username and id in that table with other fields blank. Now i want to get that updated depending on user name.

4

You’re INSERT query is wide open to potential SQL Injection attack as you’re letting user submitted data into the database without sanitizing it and either escaping it or using prepared statements

5

sounds like you want an UPDATE statement instead of an INSERT statement