PHP Notice: Undefined offset: 1

[AdRock]

I have this line of code where i want to get the value of SUM(amount)

list($number,$sum) = $this->db->query('SELECT COUNT(*), SUM(amount) FROM dc_donations');

but I get this notice

PHP Notice:  Undefined offset: 1 in C:\www\mvc\models\donate_model.php on line 42

 

At the moment the table is empty and the amount column is of type float so when i run the query through phpMyAdmin it comes back with NULL for the amount.

 

I need that amount for this line so if the table is empty, it's obviously 0

// Calculating how many percent of the goal were met:
$percent = round(min(100*($sum/GOAL),100));

[dalecosp]

And that's the error.  If $sum were a real non-zero number of some kind, you wouldn't have an NOTICE error about it being undefined...

[Stefany93]

Yeah man, you need to populate your table in order to fetch the data needed for the array.

And undefined offset almost always means that you are trying to access an un-existing element of an array. Like an accessing $array[3] while $array having only 2 elements will generate the same error.

[.josh]

also... unless you have some kind of custom coding.. $this->db->query() will almost certainly be returning a result source, not an array of values to pass to list. You will probably need to use something like $this->db->fetch_array() or similar.

[DavidAM]

Is $this->db->query() a custom method of a custom database class? In the mySql extensions, the query() method returns a resource (or object) that must be used with one of the fetch_*() functions (or methods).

 

The "undefined offset 1" error is because

list($number,$sum) = $this->db->query('SELECT COUNT(*), SUM(amount) FROM dc_donations');

// Is essentially the same as:
$temp = $this->db->query('SELECT COUNT(*), SUM(amount) FROM dc_donations');
$sum = $temp[1];
$number = $temp[0];

(yes, it assigns from right to left).

 

So the error means that method (query()) is NOT returning an array with two elements.