Error: SQLSTATE[HY000]: General error: 1 near ">": syntax error

function get_task_list($filter = null) {
    include 'connection.php';
    $sql = 'SELECT tasks.*, projects.title AS project FROM tasks
            JOIN projects ON tasks.project_id = projects.project_id';

  $where = '';

  if (is_array($filter)) {
      switch  ($filter[0]) {
          case 'project':
                $where = ' WHERE projects.project_id = ?';
                break;
          case 'category':
                $where = ' WHERE category = ?';
                break;
          case 'date':
                $where = ' WHERE date => ? AND date <= ?';
                break;

      }
  }
  $orderBy = ' ORDER BY date DESC';  
  if ($filter) {
      $orderBy = ' ORDER BY projects.title ASC, date DESC';
  }
    try {
    $results = $db->prepare($sql . $where . $orderBy);
        if (is_array($filter)) {
        $results->bindValue(1, $filter[1]);
            if ($filter[0] == 'date') {
                $results->bindValue(2, $filter[2], PDO::PARAM_STR);
            }
        }
  $results->execute();
    } catch (Exception $e) {
        echo "Error: " . $e->getMessage() . "</br>";
        return array(); //if array is returned then the foreach loop in respective place (project_list.php) is still valid and is not running the code;
    }
    return $results->fetchALL(PDO::FETCH_ASSOC);
}

<optgroup label="Date">
                        <option value="date:<?php
                        echo date('m/d/Y',strtotime('-2 Sunday'));
                        echo ":";
                        echo date('m/d/Y',strtotime('-1 Saturday'));
                        ?>">Last Week</option>
                        <option value="date:<?php
                        echo date('m/d/Y',strtotime('-1 Sunday'));
                        echo ":";
                        echo date('m/d/Y');
                        ?>">This Week</option>
                        <option value="date:<?php
                        echo date('m/d/Y',strtotime('first day of last month'));
                        echo ":";
                        echo date('m/d/Y',strtotime('last day of last month'));
                        ?>">Last Month</option>
                        <option value="date:<?php
                        echo date('m/d/Y',strtotime('first day of this month'));
                        echo ":";
                        echo date('m/d/Y');
                        ?>">This Month</option>
                    </optgroup>