notice trying to get property of non-object - php

Question

what is the error in this please help!
here is the query from mysql :
public function stgradu($condition=">=50"){
$stmt=$this->db->prepare("SELECT
courses_has_schedule.mark as mark,
Sum(courses.crs_hours) as total_hrs
FROM
courses_has_schedule
Inner Join courses ON courses_has_schedule.crs_id = courses.crs_id
Inner Join schedule ON schedule.sch_id = courses_has_schedule.sch_id
Inner Join student ON student.st_id = schedule.st_id
where
student.st_id=? AND courses_has_schedule.mark $condition");
$stmt->execute(array($this->getCurrentStudent(true)));
return $stmt->fetchAll();
}
when i run this if statement :
$stgr = $dataService->stgradu(">=50");
if(($stgr->total_hrs==7) AND ($stgradu->mark >= 50)) {
echo Yes*";
}else
echo "No";
when i run the app its gives me this error
(( Notice: Trying to get property of non-object in C:\xampp\htdocs\samer\stgr.php on line >12))
please help all!

Answer 1

fetchAll returns an array and you are trying to acces it like an object. Try this:
if(($stgr['total_hrs']==7) AND ($stgradu['mark'] >= 50)) {

Answer 2

You need to pass PDO::FETCH_OBJ to fetchAll() because it returns an associative array by default.
public function stgradu($condition=">=50"){
$stmt=$this->db->prepare("SELECT
courses_has_schedule.mark as mark,
Sum(courses.crs_hours) as total_hrs
FROM
courses_has_schedule
Inner Join courses ON courses_has_schedule.crs_id = courses.crs_id
Inner Join schedule ON schedule.sch_id = courses_has_schedule.sch_id
Inner Join student ON student.st_id = schedule.st_id
where
student.st_id=? AND courses_has_schedule.mark $condition");
$stmt->execute(array($this->getCurrentStudent(true)));
return $stmt->fetchAll(PDO::FETCH_OBJ);
}
If you are supposed to get only one row then change it to fetch(PDO::FETCH_OBJ) and your code should run fine.

Answer 3

thanx all.. i knew it by my self :P the syntax should be...
return $stmt->fetchAll()[0];