Querying MySQL results into multi-dimensional associative PHP array

Question

I'm probably overlooking a fairly simple way of doing this; perhaps someone has an idea of how to make this easy with limited looping and without an excessively long query. Let's say I have a MySQL table with data like this: (There's 12 months, and could be maybe 10 different possible grades). I'll query out just the results for a given user_id and year.

+----+---------+------+-------+-------+-------+
| id | user_id | year | month | grade | value |
+----+---------+------+-------+-------+-------+
| 1  | 1       | 2021 | Jan   | A     | 95    |
+----+---------+------+-------+-------+-------+
| 2  | 2       | 2021 | Jan   | D     | 75    |
+----+---------+------+-------+-------+-------+
| 3  | 2       | 2021 | Feb   | F     | 45    |
+----+---------+------+-------+-------+-------+

I want to be able to query the data and put it into a multi-dimensional associative PHP array. Essentially, so I can access the data like this:

echo $month_value['Jan']['D']; // Should give me 75
echo $month_value['Feb']['F']; // Should give me 45

Answer 1

Figured out a simple method that works for me:

$sql_retrieve = $con->prepare("SELECT month, grade, value
FROM table
WHERE user_id = ? AND year = ?;");
$bind_process = $sql_retrieve->bind_param('ii',$user_id,$year); 
$sql_retrieve->execute();
$result = $sql_retrieve->get_result();
$month_values = []; // initialize array
if($result->num_rows > 0 ){ // If there are results
    while($row=$result->fetch_assoc()){
      $month_values[$row["month"]][$row["grade"]] = $row["value"]; // add to array
    } // end while
} // end of if num_rows > 0

print_r($month_values); // Example

echo 'Value: '.$month_values['Jan']['D'];

This then provides the MySQL results into a multi-dimensional associative PHP array, so they can be referenced as such.