PHP while loop does not return what is the problem

What is the problem with the PHP while loop not being returned?

 Include (' include/config.php ');
Include (' include/dbclass.php ');
Session_Start ();


$db = Db::getinstance ();
$db->check_user_login (); Check if the user is logged in
$db->createcon (); Establish a connection
$user =$_session["User"];
$user = "Libero"; Test temporary use
Execute User Data table to select User Data
$sql _user = "SELECT * from user where user = ' $user '";
$user _array = $db->fetch_array ($sql _user);




Perform yytable data acquisition yytable all data
$sql _yytable = "SELECT * from yytable where uid = ' $user _array[0] '";

echo "

















 
 
  
  "while ($yytable _array = $db->fetch_array ($sql _yytable)) {echo"
  
  
     "; Echo" 
    "; Echo" 
    "; Echo" 
    "; Echo" 
    "; Echo" 
    "; Echo" 
    "; Echo" 
   ";} echo " 
  
 
   
". $yytable _array[0]."
". $yytable _array[1]."
". $yytable _array[2]."
". $yytable _array[3]."
". $yytable _array[4]."
". $yytable _array[5]."

 
 
";

Dbclass


 Class db{
private static $dbhost = "localhost";
private static $dbuser = "root";
private static $password = "";
private static $dbname = "YY";
private static $instance = NULL;
 
 
constructor function
Private Function _construct () {}
Instantiation of
public static function getinstance () {
if (self:: $instance = = null) {
Self:: $instance = new db ();
}
Return self:: $instance;
}
Connecting to a database
Public Function Mycon () {
@mysql_connetc (self:: $dbhost, Self:: $dbuser, Self:: $password);

}
Select Database
Public Function Selectdb () {
$mysql _select_db (self:: $dbname);

}

Create a Connection connection database
Public Function Createcon () {

Mysql_connect (self:: $dbhost, Self:: $dbuser, Self:: $password);
mysql_select_db (self:: $dbname);
}


Get $sql result set based on query criteria
Public Function Fetch_array ($sql) {
   
if ($result = $this->query ($sql))
{
$rs = Mysql_fetch_array ($result, Mysql_both);
return $rs;
   
}
else {echo "data query failed";}

}

Database query Execution statement
Public Function Query ($sql) {
mysql_query ("Set names UTF8");
return mysql_query ($sql);
}

Loop more result set get array

Public Function Loop_query ($result) {
return mysql_fetch_array ($result);


}




To close a database connection

Public function Close () {

return Mysql_close ();

}



}








}



       










?>

------Solution--------------------
Get $sql result set based on query criteria
Public Function Fetch_array ($sql) {
if ($result = $this->query ($sql)) {// This judgment has been established since the use of while, so it's a dead loop.$rs = Mysql_fetch_array ($result, Mysql_both);
return $rs;
} else {
echo "Data query failed";
}
}
------Solution--------------------
while ($yytable _array = $db->fetch_array ($sql _yytable)) {
Always executes the query $db->fetch_array ($sql _yytable) and always returns the first result

Your Fetch_array method can only be used to query a record of the occasion
You should write another Fetch_all method, query and return all results
------Solution--------------------

 
 Public function Fetch_all ($sql) {
 if ($result = $this->query ($sql)) 
 {
 while ($r = Mysql_fetch_array ($result, Mysql_both)) {
 $res [] = $r; 
 