$id = 2;
$q = "SELECT * FROM modx_site_content WHERE parent = ':parent'";
$query = new xPDOCriteria($this->modx, $q);
$query->prepare();
$query->stmt->bindParam(':parent', $id, PDO::PARAM_INT);
$query->stmt->execute();
MODX Staff
You have to bind before preparing or pass the parameter bindings in the call to execute().
$q = "SELECT * FROM modx_site_content WHERE parent = :parent";