Query rows from a database table in PHP
See here for the original answer.
You are never using $condition1 and $condition2 after you give them their static values, which might be the problem here.
Another thing I would consider is switching from your current $result assignment to this:
$sql = "SELECT * FROM client_scope WHERE client_scope_id = '$siteID'
AND client_Id='".$_SESSION['clientId']."'";
$result = $conn->query($sql) or die($conn->error);
In your current query, you didn't include single quotes around $siteId, which was likely one of the problems because I had the same issue with a query yesterday.
Another problem was you had a set of single quotes inside another set of single quotes with your client_Id assignment, which doesn't work. Using the period operator, this method joins the $_SESSION part of the query with the rest. This is explained here.
Finally, the or die($conn->error) part of $result typically shows you errors that may exist like this in your queries in the future. For an explanation of this, see here.
This may be a personal preference, but I have always seen your foreach loop written as something similar to this:
while ($row = $result->fetch_assoc()) {
echo json_encode($row);
}
I don't know if there is any functional difference, but it may be another factor.