php - mysqli_stmt::bind_param(): Number of elements in type definition string doesn't match number of bind variables -

i developing class mysql query

main purpose run query (select, insert, update) if it's select should return result data, , if it's updata or insert should return number of rows affected.

but following code throws error error in line if($stmt->bind_param($types, $escaped))

    <?php     class sqli{          public $mysqli;         public function __construct($host, $username, $password, $dbname){           $this->mysqli = new mysqli($host, $username, $password, $dbname);           if($this->mysqli->connect_errno){            echo $this->mysqli->connect_error;            die("could not connect mysql database");           }         }         public function query($qry,$types,$array){           if(!empty($qry)){                 if($stmt = $this->mysqli->prepare($qry)){               if(count($array)>0 &&!empty($array)){              $escaped = array();                foreach($array $value){                  $value= $this->mysqli->real_escape_string($value);                  $escaped[]=$value;                    }                $escaped = join("','",$escaped);                $escaped = "'".$escaped."'";                echo count($types);                echo $escaped;                echo count($escaped);                if(!empty($types)){                  if($stmt->bind_param($types, $escaped)){                    if($stmt->execute()){                      if($prefetch = $stmt->get_result()){                          $result = array();                        while($row=$prefetch->fetch_array()){                          $result[]=$row;                        }                        return $result;                           }elseif($stmt->affected_rows){                        return $stmt->affected_rows;                      }                                      }                  }                }                               }else{                if($stmt->execute()){                  if($prefetch = $stmt->get_result()){                    $result = array();                    while($row=$prefetch->fetch_array()){                      $result[]=$row;                    }                    return $result;                        }elseif($stmt->affected_rows){                    return $stmt->affected_rows;                  }                                  }              }            }            }else{            return false;               }        }     }   $mysqli = new sqli($params['db_host'],$params['db_user'],$params['db_pass'],$params['db_name']);   $qry = "select * tbl_chat from_id=? , to_id=?";   $result = $mysqli->query($qry,'ii',array('717','1543')); 

if run query select * tbl_chat works fine

please