ohctech_p8/medicine_details_chart.php

<?php
include('includes/config/config.php');

$labels = array();
$data = array();

$ohc_id = $_SESSION['current_ohcttype'];
$sql_query = "SELECT ti.item_name, COUNT(si.item_id) + COUNT(t.item_id) as count
              FROM stock_issue_items si
              LEFT JOIN tbl_items ti ON si.item_id = ti.item_id
              LEFT JOIN treatment t ON si.item_id = t.item_id
              WHERE ti.ohc_type_id = ?
              GROUP BY ti.item_id
              ORDER BY count DESC
              LIMIT 0,10";

$stmt = mysqli_prepare($conn, $sql_query);

if (!$stmt) {
    error_log("Error preparing statement: " . mysqli_error($conn));
    die();
}

mysqli_stmt_bind_param($stmt, "s", $ohc_id);
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);

while ($row = mysqli_fetch_assoc($result)) {
    $name = $row['item_name'];
    $count = $row['count'];

    $labels[] = $name;
    $data[] = $count;
}

mysqli_stmt_close($stmt);

$response = array(
    'labels' => $labels,
    'data' => $data
);

echo json_encode($response);