Display group by table from mysql in php - php

Question

I have a query in mysql which will return a table grouped by some fields. How can I echo these results?
Here is piece of my code.
$stmt = $con->prepare("
SELECT classSubject
, COUNT(*) cnt
from Class
where grade=?
and department=?
and classGroup IN(?,3)
GROUP
BY classSubject;
");
$stmt->bind_param("isi", $grade, $department, $classGroup);
//executing the query
$stmt->execute();
What should I do after this so that I can echo all the result?

Answer 1

I recommend reviewing a good site which can serve as an example of what syntax to use, such as this one.
$sql = "SELECT classSubject, COUNT(*) cnt FROM Class ";
$sql .= "WHERE grade = ? AND department = ? AND (classGroup = ? OR classGroup = 3) ";
$sql .= "GROUP BY classSubject";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("isi", $grade, $department, $classGroup);
$stmt->execute();
$result = $stmt->get_result();
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc()) {
echo "(classSubject, count) = (" . $row['classSubject'] . ", " . $row['cnt'] . ")";
}
}
Note that I add an alias to the COUNT(*) term in the select so that we can easily refer to it by name in PHP. You could also just refer to columns using their numeric indices, but going by name is an easier and safer way to do it.

Answer 2

After reading Tim Biegeleisen's answer and doing a bit of surfing, I came up with this solution. After executing the query:
$response = array();
$response['success']=true;
$stmt->bind_result($classSubject,$cnt);
while ($stmt->fetch())
{
$response[$classSubject]=$cnt;
}
echo json_encode($response);
Hope this helps someone.