Sql request problem

Hi
until now I used php 5.6 and for sql request i had created a dynamic syntax like this:

function getInfo($table,$where,$field,$path="",$single="yes"){
	$mySforceConnection=connectTOsf($path);
    $res=array();
    $tab_field=array();
  $contact="";
  $x=0;$z=0;
  try{ 
    $query = "SELECT ".$field." from ".$table." ".$where; 
  	$response = $mySforceConnection->query($query);   
    $queryResult = new QueryResult($response);
    $tab_field=explode(",",$field); 
  	for ($queryResult->rewind(); $queryResult->pointer < $queryResult->size; $queryResult->next()) 
  	{  
  		$record=$queryResult->current();
  		for($i=0;$i<count($tab_field);$i++)
               {  
                   if($tab_field[$i]=="Id") $value=$queryResult->current()->Id;
                   else                     $value=$record->fields->$tab_field[$i];
                   ..... suite du traitement
               }
       }
.........

It worked very well, but now with php7 the $value (not ID whose is static) are empty, and the values contain in $tab_field[$i] are correct.
Is somebody can help me please?
Thanks a lot in advance