title: Warning: mysqli_query() expects parameter 2 to be string, object given in
body: <p>Good morning!</p>
  
  <p>I'm new in PHP. i'm trying to make work this scrpt but is showing me this problem. It's a forma that modifies some records in a mysql database. The codes gets the data but it shows me that mistake and when i run modify it shows me several problems.... </p>
  
  <blockquote>
    <p>Warning: mysqli_query() expects parameter 2 to be string, object given
    in C:\wamp\www\CTE\formedicion.php on line 15</p>
  </blockquote>
  
  <p>I still don't know how to fix it. I really appreaciate your help.</p>
  
  <p>Thanks!</p>
  
  <pre><code>&lt;body&gt;
  
  &lt;?php
  
  include "conexiondb.php";
  
  if(!isset($_POST['submit'])){
  
  //$busqueda=$con-&gt;query(    
  $muestra=$con-&gt;query("SELECT * FROM clientes C INNER JOIN producto P ON C.serial  = P.serial WHERE P.serial = $_GET[serial]");
  
  //mysqli_query($con,$sql);  
  mysqli_query($con,$muestra);
  
  $person=$muestra-&gt;fetch_array();
  }
  ?&gt;
  
  &lt;form action="&lt;?php echo $_SERVER['PHP_SELF'];?&gt;" method="post"&gt;
  
    cliente&lt;input type = "text" name="inputcliente" value = "&lt;?php echo $person['cliente']; ?&gt;" /&gt;&lt;br/&gt;
  
    cedula &lt;input type = "text" name="inputcedula" value = "&lt;?php echo $person['cedula']; ?&gt;" /&gt;&lt;br/&gt;
  
  &lt;input type="hidden" name="serial" value="&lt;?php echo $_GET['serial'];?&gt;"/&gt;
  &lt;input type = "submit" name = "submit" value= "Modificar"/&gt;
  &lt;/form&gt;
  
    &lt;?php
    if (isset($_POST ['submit'])){
  
  $u = "UPDATE cliente SET'cliente'='$_POST[inputcliente]','cedula' = '$_POST[inputcedula]' WHERE serial=$_POST[serial]";
  mysqli_query($con,$u);
  
  echo "El usuario ha sido modificado";
  header ("Location:busca.php");
  
  } else {
  
        }
  
    ?&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>