SQL query

$isodate = sprintf('%d-%02d-01', $yearer, $mr);  // format 1st of the month

$query = <<<SQL
    SELECT EXTRACT(MONTH FROM ?) AS areacharttime,
           COUNT(*) AS areachart_count,
           (SELECT COALESCE(SUM(counting), 0)
              FROM total_visit
             WHERE count_date BETWEEN ? AND ? + INTERVAL '1' MONTH - INTERVAL '1' DAY) AS areachart_count_all
      FROM unique_total_visit
     WHERE visit_date BETWEEN ? AND ? + INTERVAL '1' MONTH - INTERVAL '1' DAY
    SQL;

$stmt = $db->prepare($query);
$stmt->execute([$isodate, $isodate, $isodate, $isodate, $isodate]);
$row = $stmt->fetch(PDO::FETCH_ASSOC);